Need 2nd opinion 2 ton or 3 ton?

[Motortiger]

I'm a newbie here. I'm about to sign a contract for a new Trane XL16i heat pump. I have a oil boiler I'm going to use for backup heat to carry the heating load under 32 degrees. My Trane sales guy thinks I should step up to the 3 ton to better carry the heating load. I have a fairly well insulated 1200 square foot ranch in the Springfield Mass area. From all the stuff I've read here it's better to not oversize.In my area I have many more heating days than cooling. I think he told me my total heat loss at 0 degrees was less than 40,000m btu per hour and my cooling load was under two tons. The big question is will a 2 ton carry the load down to 32 degrees? The $600 rebate brings the cost down good for the 2 ton but the extra for the three ton is a little pricey. Any opinions would be appreciated.

Thanks

[RoBoTeq]

Heat pump should be sized to cooling conditions, not heating.

[beenthere]

50/50 chance weather the 2 ton will handle the load at 32* or not. I don't have your load calcs infront of me
Good chance that the humidity in the house in the summer at milder OD temps will be high, even with 2 stage if you go with the 3 ton.


Are you using a hydro coil on the air handler.
Or just going to use the existing baseboard/cast iron rads.

[Motortiger]

My house was built 30yrs ago with just a heat pump for heat.I have a hydro coil in the air handler now. I switched to oil heat about 10 years ago. I think the old heat pump was a 2.5 or 3 ton Trane Weatherthron. I was looking at just getting a AC unit, untill I found out I could save money going with a heat pump from the high cost of oil now. I want to save money on heating but not get up at night from the house being muggy during the summer.

[beenthere]

On older systems.
If the duct work is undersized. The lack of air flow helped keep the humidity under control.
Now, if you put in a VS blower. The blower will speed up to move the set air flow. This can make the ductwork noisey, the A/C not dehumidify right, and burn out the VS blower.

Is this the only estimate you have.

Or did other companies also come up with 2 tons. But this is the only one that also suggested a 3 ton.

[dan sw fl]

I'm a newbie here. I'm about to sign a contract for a new Trane XL16i Heat Pump.

I have a oil boiler I'm going to use for backup heat to carry the heating load under 32 degrees.

My Trane sales guy thinks I should setup to the 3 ton to better carry the heating load. I have a fairly well insulated 1200 square foot ranch in the Springfield Mass area.

From all the stuff I've read here it's better to not oversize. I think he told me my total heat loss at 0 degrees was less than 40,000 Btuh
and my cooling load was under two tons.

Any opinions would be appreciated.

3-Ton ...
Balance point is likely ~ 28'F

ASHRAE Design Conditions
Summer 87' F / 71' F DB/WB ... 64' F Dew Point
Winter 11' F

390 Hours > 79'F from temperature bin data

http://www.wunderground.com/history/airport/KCEF/2007/3/22/CustomHistory.html?dayend=21&monthend=3&yearend=2008&req_city=NA&req_state=NA&req_statename=NA

[Motortiger]

The other estimate I had said two ton would be better for cooling but you could go with a 2.5 ton heat pump but cooling would not be as good. It was up to me. I had a third estimate done before I thought about a heat pump and they suggested a 2 ton AC unit.

[beenthere]

Being a 2 stage, you might get away with oversizing by a ton.
I wouldn't risk it.

[Motortiger]

Back when I only used the old heat pump the resistance electric heat would only kick in fist thing in the morning with temps near zero. My thought is with oil backup heat I don't need a 3 ton anymore. That a 2 ton would be better for summer and still save me a lot of money heating with oil, but I'm no expert that's why I'm glad I found this forum.:)

[skippedover]

Use the attachement. Select the right company and they'll give you the right advice. It's really as simple as that.

[BaldLoonie]

3 ton for 1200 sq ft in Mass? All glass? No insulation? Is he nuts? An oversized 2 stage is an expensive single stage. You'll sit on low all the time, at least in cooling mode. What's the point? Yea, it might gain you a lower balance point in heating but sure doesn't make sense to me.

A GOOD dealer should be able to calculate balance point for you assuming he's run a load calc on your house and knows the outputs of his heat pump.

One drawback to Trane is lower heat outputs. You might look around and find a 2 ton with a higher capacity that lowers the balance point without grossly oversizing in cooling mode.

16i 2 ton, heat output is 20,000 BTU or 17% lower than you'd expect from a "2 ton"

16i 3 ton, heat output is 30,000 to 32,000 BTU depending upon AH.

If you look around you can find systems where the capacity is much higher on heating.

[smokin68]

In Mass you focus on heating not cooling. With a two stage system, you can definetely go bigger to help you in the heating mode. Otherwise, just go with oil and a staight-cool. JMO.

[tigerdunes]

MotorTiger

The Trane 16XLi HP requires a var speed blower on an air handler or furnace to operate correctly.

For the price, the 16XLi has very poor performance numbers particularly in heating BTUs. You are paying for a three ton but getting closer to 2 1/2 ton in heating BTUs. You might consider a 2 1/2 or 3 ton XL15i that has good numbers and use the Honeywell VP IAQ stat.

I think your strategy is good-you just have the wrong equipment.

You need a load calculation performed to verify size.

And I would compare fuel costs-doesn't Ma have expensive electric rates?
see fuel comparison calculator link below.

IMO

http://www.warmair.com/html/fuel_cost_comparisons.htm

[Freezeking2000]

In Mass you focus on heating not cooling. With a two stage system, you can definetely go bigger to help you in the heating mode. Otherwise, just go with oil and a staight-cool. JMO.


I agree, We do not have the high humidity issues for many days. I would not go to a 3 ton unit unless it was 2 stages with that small of a home. Can the ducts handle 3 tons? I would think not in that small of a home.

[Motortiger]

I think I could save $300 maybe more a year with a heat pump. I use about 500 gallons of oil a year for heat with my boiler at 80% afue. My electric rate is .15 per kwh and last fill up was about $3.50 a gallon and sure to go up.

[RoBoTeq]

In Mass you focus on heating not cooling. With a two stage system, you can definetely go bigger to help you in the heating mode. Otherwise, just go with oil and a staight-cool. JMO.
Nope; always size the refrigeration system for cooling. Your secondary heating should be what makes up the difference. If electricity is high in your area, install a fossil fuel system such as a furnace or hydronic coil fed by a boiler or water haeater.

Oversizing a refrigeration system is just asking for trouble.

[smokin68]

Nope; always size the refrigeration system for cooling. Your secondary heating should be what makes up the difference. If electricity is high in your area, install a fossil fuel system such as a furnace or hydronic coil fed by a boiler or water haeater.

Oversizing a refrigeration system is just asking for trouble.


What trouble would oversizing a two-stage cause in this case? Their climate isn't a hot-humid sweat box like Florida. They use a/c MAYBE 3 months a year. They use heat 6 months. The only problem with an oversized system is lack of humidity removal due to short-cycling which can cause mold problems.This can be sorted out with a load calc and the output of stage 1.The equipment can be protected with time delays. I know what the "book" says, but a undersized heatpump would be worthless in the winter. You'll be running aux constantly. You're better off with a straight a/c and oil/gas then.

[bob hubbard]

3 ton for 1200 sq ft in Mass? All glass? No insulation? Is he nuts? An oversized 2 stage is an expensive single stage. You'll sit on low all the time, at least in cooling mode. What's the point? Yea, it might gain you a lower balance point in heating but sure doesn't make sense to me.

A GOOD dealer should be able to calculate balance point for you assuming he's run a load calc on your house and knows the outputs of his heat pump.

One drawback to Trane is lower heat outputs. You might look around and find a 2 ton with a higher capacity that lowers the balance point without grossly oversizing in cooling mode.

16i 2 ton, heat output is 20,000 BTU or 17% lower than you'd expect from a "2 ton"

16i 3 ton, heat output is 30,000 to 32,000 BTU depending upon AH.

If you look around you can find systems where the capacity is much higher on heating.

I would agree to looking at a system that has a 2.5 ton rating ! Over a half a ton wont hurt ya in cooling , and will help the heating the other 6 months .

[beenthere]

You can't rely on first stage to remove enough moisture on a HP that has been sized to the heating load, in some areas.
The SHR will be too high for the short run times during the mild weather.
You won't have the long run times that many units need to keep the humidity in check.

We've been sizing HP's to the cooling load(some times you go up a half ton) for a long time up here, and it works good for both seasons.

[BaldLoonie]

The net effect of the 16i on low is around 75% of high. That means even in very mild weather when a little cooling is on for drying out the air and taking out a little heat, you are getting more cooling than the 2 ton would put out. The 16i on low in some matches has a .8 SHR ratio, lousy, that does little to suck moisture out, especially with a short run. Most single stage Trane systems run around a .7 SHR which means GALLONS more moisture out in a day.

Suppose they do put in a 3 ton duct system for 1200 sq ft, could get a bit drafty when it switches to high.

[RoBoTeq]

Just because there is not as much humidity as there is in more southern, coastal regions, does not mean that humidity is not an issue.

The lower cooling demand means that the systems have less run times. Less run times mean less dehumidification. Increasing the size of the system increases the already problematic dehumidification issues. You'll wind up needing to lower the temperature in the cooling mode to compensate for the humidity issues. This gives rise to an earlier cooling issue of being cold and clammy feeling rather then cool and dry.

[platchford]

Have you considered a 2.5 ton or is that not available? Also, if you plan on running it to 32* then you probably want to be sure it has a crankcase heater. At 30-35 degrees without a crankcase heater the humidity and snow will likely make your HP frost up more frequently then in the same temperature with a lower humidity. What are you using for a fossil fuel kit? If you are using a VisionPro then in my experience you have to choose 30 or 35 because the compressor lockout temps are every 5 degrees.

I would still size for cooling. If you undersize for heating and have to set the lockout temp to 35* or 40* then you still have the oil for backup which is no big deal. However, if you oversize for cooling then you are going to be uncomfortable and you have no secondary system to fall back on. Personally, I would probably go with 2 ton or 2.5 ton... but I haven't seen the load calc for your home.

[platchford]

I know what the "book" says, but a undersized heatpump would be worthless in the winter. You'll be running aux constantly. You're better off with a straight a/c and oil/gas then.

How do you figure that you'd be better of with straight A/C then? Even if you're running aux more often, you'd still have what, several months minimum where the temperatures are easily 40 to 65 degrees?

Suggestion get a load calc. If you have one already then have them adjust the load calc for a OD temperature of 30 degrees and see how many BTUs are needed. Then, look at the specs on the possible heat pumps and look at the estimated heating BTUs provided at said temperature. Is it enough? This isn't rocket science! :p

[Motortiger]

Have you considered a 2.5 ton or is that not available? Also, if you plan on running it to 32* then you probably want to be sure it has a crankcase heater. At 30-35 degrees without a crankcase heater the humidity and snow will likely make your HP frost up more frequently then in the same temperature with a lower humidity. What are you using for a fossil fuel kit? If you are using a VisionPro then in my experience you have to choose 30 or 35 because the compressor lockout temps are every 5 degrees.

I would still size for cooling. If you undersize for heating and have to set the lockout temp to 35* or 40* then you still have the oil for backup which is no big deal. However, if you oversize for cooling then you are going to be uncomfortable and you have no secondary system to fall back on. Personally, I would probably go with 2 ton or 2.5 ton... but I haven't seen the load calc for your home.

I'm going to ask to see the load calculation sheet for my house. I have R38 in the ceiling and R11 under the foor. If a 2 ton is under sized for heating a little I think that might be better. I'm going to ask to see a balance point sheet with my Kwh rate at 0.15 and and heating oil at $3.50 a gallon with my heat loss. I'm thinking maybe the 2.5 ton XL15i would be a better choice. But I saw lower specs for HSPF with that model than the 16i or 14i but on some web sites they had it at the same. I have a hydro coil in the air handler for backup heat with my oil boiler. The quote I have is with a variable speed air handler.

[tigerdunes]

motortiger,

Trane's XL15i 2 1/2 ton HP paired with var spd air handler has very good performance numbers plus it has electronic demand defrost feature.

1382160 Active OEM XL15I WEATHERTRON TRANE 4TWX5030A1 4TEE3F39A1 30000 13.00 15.75 30000 9.00 18000

numbers provided from CEE HVAC directory

IMO
:)

[Motortiger]

I'll trying to figure what I could save with running a heat pump with my oil heat for backup. What would the average COP be? Is it ok to figure I would use the heat pump for 1/2 of my seasonal btu's?

[Swampfox]

Nope; always size the refrigeration system for cooling. Your secondary heating should be what makes up the difference. If electricity is high in your area, install a fossil fuel system such as a furnace or hydronic coil fed by a boiler or water haeater.

Oversizing a refrigeration system is just asking for trouble.

I tend to agree, but

From ACCA Manual S....


In colder climates, heating efficiency is more important than cooling efficiency, In this case the cooling equipment can be oversized in order to obtain more heating capacity, a lower thermal balance point and greater heating efficiency, when heating costs are the primary concern the heat pump sensible capacity may exceed the Manual J sensible load by as much as 25%

I would think having a 2 speed system oversized would create less of an issue when sizing equipment for heating load, although it would basically be an expensive single stage system most of the summer.

[dan sw fl]

It is quite easy to determine relatively accurate Energy Cost
and What IF scenarios
if you have a valid Heat Transfer and equipment model
along with temperature bin data.

[RoBoTeq]

I tend to agree, but

From ACCA Manual S....



I would think having a 2 speed system oversized would create less of an issue when sizing equipment for heating load, although it would basically be an expensive single stage system most of the summer.
I am not usually one to buck up against sources such as ACCA, but this just goes against everything we have been taught as well as the laws of physics.

Then again, even at 25%, that is not as much as going from 2 ton to 3 ton which would be 50% more.

[dash]

I am not usually one to buck up against sources such as ACCA, but this just goes against everything we have been taught as well as the laws of physics.

Then again, even at 25%, that is not as much as going from 2 ton to 3 ton which would be 50% more.

But it certainly does leave open using a 2.5 ton instead of the 2 ton required by the load calc as you stated ,doesn't it???

[RoBoTeq]

But it certainly does leave open using a 2.5 ton instead of the 2 ton required by the load calc as you stated ,doesn't it???
Under the circumstances and with the ACCA statement I suppose that would be a viable compromise. Just goes against what I believe to be proper according to all of my training.

Also, as you have mentioned earlier, reducing the blower speed would bring the dehumidification values back up. I would only attempt to the reduced air with a VS blower though.

[rponson]

Bald Loonie put it best. "an Oversized 2 speed is just an expensive single speed."

Size the heatpump for your cooling load

[dash]

Under the circumstances and with the ACCA statement I suppose that would be a viable compromise. Just goes against what I believe to be proper according to all of my training.

Also, as you have mentioned earlier, reducing the blower speed would bring the dehumidification values back up. I would only attempt to the reduced air with a VS blower though.

"All of my training" care to expand on that ,since you are going against the industry standards?


Also why only if a variable speed blower,just wonder why that would be an issue that couldn't be overcome by a technician.

[beenthere]

At your posted $0.15 KW and $3.50 per gal oil.
Your HP will be more efficient then oil as long as your COP is above 1.4

So your lock out should be when the HP's COP drops to 1.4 and lower.
Since your using a hydro coil, you can run both the HP and boiler at the same time, unlike direct fired forced air systems.

[platchford]

I tend to agree, but

From ACCA Manual S.... "In colder climates, heating efficiency is more important than cooling efficiency, In this case the cooling equipment can be oversized in order to obtain more heating capacity, a lower thermal balance point and greater heating efficiency, when heating costs are the primary concern the heat pump sensible capacity may exceed the Manual J sensible load by as much as 25%"

I would think having a 2 speed system oversized would create less of an issue when sizing equipment for heating load, although it would basically be an expensive single stage system most of the summer.

Seeing as I don't have an ACCA Manual S to check this myself, I have one quick question. Is the manual at this point referring particularly to a straight HP or a HP with Fossil Fuel or is it just a general statement? I also notice that it says it "can be oversized" for cooling not it "should be oversized" for cooling. :confused:

[beenthere]

It also states you can over size HP's by 25% in Manual J.

As far as I know, it doesn't matter what your aux heat is. The idea is to use the more efficient HP as much as possible for heating, without compromising humidty removal in the summer.

[tigerdunes]

I'll trying to figure what I could save with running a heat pump with my oil heat for backup. What would the average COP be? Is it ok to figure I would use the heat pump for 1/2 of my seasonal btu's?

motortiger

On the XL15i that I listed, I would use a COP of 2.75 and say that the HP without aux heat strips would be effective down to 32-35 degrees-an educated guesstimate. Of course, you will lose COP and BTUs as the temperature drops. With an added heat strip like a 7KW, you can extend the utilization of a HP and still be cheaper than running oil. Ask your dealer to calculate the number of BTUs required to heat your home at 35 degrees, 30 degrees, 25 degrees. This will give you an idea of the effectiveness of a heat pump.

Plug the numbers into fuel comparison calculator link.

IMO

http://www.warmair.com/html/fuel_cost_comparisons.htm

[everythingair]

It also states you can over size HP's by 25% in Manual J.

As far as I know, it doesn't matter what your aux heat is. The idea is to use the more efficient HP as much as possible for heating, without compromising humidty removal in the summer.

This is a bit of a Catch-22 though. You cannot effectively oversize cooling capacity without compromising humidity control. The only place this would effectively work is a place where the humidity level never rises above 35% at 72 degrees fahrenheit. The only places these conditions exist are desert like areas such as certain parts of Arizona and Utah etc. or in tundra regions where cooling would not be needed.

[beenthere]

Not 100% true.

A slightly over sized system can keep humidity to 55%.
The upper end, but still safe.

If this was not true, then you couldn't use a 5 ton unit, on a house that comes out to 4.25 tons.

[everythingair]

Not 100% true.

A slightly over sized system can keep humidity to 55%.
The upper end, but still safe.

If this was not true, then you couldn't use a 5 ton unit, on a house that comes out to 4.25 tons.

The very reason the HVAC industry does not manufacture a half sized four ton system is that in this capacity there is marginal percentile differential.

The difference between a 4.25 ton load and a 5 ton system is only 15%.

[beenthere]

You ever install a 1.5 ton A/C in a house that only needs 1 ton.
Thats 50% oversized.

And 5 divided by 4.25=17.6% :)

Oversize %
1.5 to 2=33%
2 to 2.5=25%
2.5 to 3=20%

Undersized %
2 to 1.5=25%
2.5 to 2=20%
3 to 2.5=17%

[RoBoTeq]

You ever install a 1.5 ton A/C in a house that only needs 1 ton.
Thats 50% oversized.

And 5 divided by 4.25=17.6% :)

Oversize %
1.5 to 2=33%
2 to 2.5=25%
2.5 to 3=20%

Undersized %
2 to 1.5=25%
2.5 to 2=20%
3 to 2.5=17%
You get your percentage by dividing 4.25 by 5, which is .85 or meaning that 4.25 is 85% of 5 which means that there is a 15% difference.

The differential between the sizes is the same whether oversized or undersized.
Between;
1.5 and 2 = 25%
2 and 2.5 = 20%
2.5 and 3 = 16.66%

[beenthere]

I think my way is right. :)

And will continue to use it. :D

[RoBoTeq]

I think my way is right. :)

And will continue to use it. :D
Creative math has always been of value in some way;)

[Motortiger]

The plumbing and Heating guy that is giving me the quote is one I got thru Home Depot. I thought Home Depot guarantees the quality of the contractor's work. My sister just told me there was a big thing in the news a while back of the Home Depot contractors doing shoddy work. Before I sign anything what's the best way to make sure they do quality good work. Should I be concerned here.

[dash]

The plumbing and Heating guy that is giving me the quote is one I got thru Home Depot. I thought Home Depot guarantees the quality of the contractor's work. My sister just told me there was a big thing in the news a while back of the Home Depot contractors doing shoddy work. Before I sign anything what's the best way to make sure they do quality good work. Should I be concerned here.

I'd be concerned,but no more then if you weren't going thru HD,they have some great contractors that do their work.

What city/state are you in?

[Motortiger]

I'm in Hadley Mass the Contractor is EWS Plumbing and Heating out of Monson Mass.

[beenthere]

Get references from the contractor. Then go look at his work.

[Motortiger]

I just got off the phone with the Trane sales guy. He's going to email me tonight the performance data sheets for the 15i in 2ton and 2.1/2 ton and the 16i in 2ton and three ton and the economic balance point sheet for my heat load and electric and oil cost. I asked him about my ducts being to small for three ton. He said they are too small for a three ton, but would only be in 2nd stage for a couple minutes before it kicked down to 1st for cooling. Well I said how about heating it's going to be in 2nd stage much longer. He said they could adjust the variable speed AHU for it. I'll post again after I get the sheets emailed to me. One other thing I want to say that's not about my sizing a heat pump is I've posted on other forum sites about different topics but you guys on this forum are the best. Thanks for all the help so far.:)

[beenthere]

Some manufacturers run the blower in a slower speed to keep the discharge air temp warmer. Its a nice feature. But it also reduces teh efficiency of the heat pump.
If he adjust the blower speed in heat to run slower in second stage then normal, he is also reducing its heating efficiency.

Just a FYI.

[dash]

I just got off the phone with the Trane sales guy. He's going to email me tonight the performance data sheets for the 15i in 2ton and 2.1/2 ton and the 16i in 2ton and three ton and the economic balance point sheet for my heat load and electric and oil cost. I asked him about my ducts being to small for three ton. He said they are too small for a three ton, but would only be in 2nd stage for a couple minutes before it kicked down to 1st for cooling. Well I said how about heating it's going to be in 2nd stage much longer. He said they could adjust the variable speed AHU for it. I'll post again after I get the sheets emailed to me. One other thing I want to say that's not about my sizing a heat pump is I've posted on other forum sites about different topics but you guys on this forum are the best. Thanks for all the help so far.:)

Good question very sharp on your part,there's no such adjustment that should be made for heating,if the ducts are to small.You'll just never know until the issues rear their ugly head.

[Motortiger]

I just got the economic balance point sheets for the 15i in 2 ton and 2 1/2 ton and the 16i in 3 ton. The 15i two ton is 1450 btu short at 37 degrees. The 15i 2 1/2 ton is 350 btu's short of carrying the load at 27 degrees. The 3 ton 16i is 1800 btu's short at 32 degrees. The other thing I saw is the COP is much better on the 15i than the 16i. The COP on the 16i at 32 degrees is 2.6 and the 15i 2 1/2 ton is 3.09 at 32 degrees. I would post the sheets but I don't know how to save and link them to my verizon web space yet. If you want to look at them I can email to you. It looks to me like the 15i is much better for heating. That's the one to get.:)

[catmanacman]

what about a 19i

[tigerdunes]

I just got the economic balance point sheets for the 15i in 2 ton and 2 1/2 ton and the 16i in 3 ton. The 15i two ton is 1450 btu short at 37 degrees. The 15i 2 1/2 ton is 350 btu's short of carrying the load at 27 degrees. The 3 ton 16i is 1800 btu's short at 32 degrees. The other thing I saw is the COP is much better on the 15i than the 16i. The COP on the 16i at 32 degrees is 2.6 and the 15i 2 1/2 ton is 3.09 at 32 degrees. I would post the sheets but I don't know how to save and link them to my verizon web space yet. If you want to look at them I can email to you. It looks to me like the 15i is much better for heating. That's the one to get.:)

motor

I would go with the 2 1/2 ton XL15i and suggest the following configuration that has excellent performance numbers.

1382160 Active OEM XL15I WEATHERTRON TRANE 4TWX5030A1 4TEE3F39A1 30000 13.00 15.75 30000 9.00 18000

Also do not use Trane's stat-go with the Honeywell VP IAQ that controls blower speed for superior dehumidification in cooling mode. I would also suggest a small heat strip like a 5KW or 7.5KW that will extend the utilization of your HP and still be less expensive to operate than $3.50/gal oil.

IMO
Good Luck!
:)

[berg2666]

Do NOT sign that contract. You will not be happy.

And in the whole thread the was only ONE mention of LOAD CALCULATION.

We all know that that is what determines system requirments. and all the other babble of effeciencies and seers and other stuff means nothing without a proper LOAD CALCULATION done.


If he will not do a load calc on your house then he is wasting his time, and dont let the guy just walk around looking at the ceiling and floors and walls and say he did a load calc.

There are specific questions that we all ask to do one, no matter how they ask the question, we all ask the same one someway shape or form

[berg2666]

The plumbing and Heating guy that is giving me the quote is one I got thru Home Depot. I thought Home Depot guarantees the quality of the contractor's work. My sister just told me there was a big thing in the news a while back of the Home Depot contractors doing shoddy work. Before I sign anything what's the best way to make sure they do quality good work. Should I be concerned here.


Do NOT sign that contract. You will not be happy.

And in the whole thread the was only ONE mention of LOAD CALCULATION.

We all know that that is what determines system requirments. and all the other babble of effeciencies and seers and other stuff means nothing without a proper LOAD CALCULATION done.


If he will not do a load calc on your house then he is wasting his time, and dont let the guy just walk around looking at the ceiling and floors and walls and say he did a load calc.

There are specific questions that we all ask to do one, no matter how they ask the question, we all ask the same one someway shape or form

[Motortiger]

He did do a load calculation it was 38,000 btu's about the same number's the heating contractor gave me when I switched to oil heat in back 1995. Better Business Bureau had them for 0 complains for the past 36 months. I'm going to check references too.

[tigerdunes]

motortiger

what is your summer cooling load?
based on what indoor temp and what outside temp?

TD

[Motortiger]

I don't see the summer cooling load only Heat loss. Winter OD Design 7. I have to ask.

[Motortiger]

I did have another contractor tell me it was a little under 24,000 btu's.

[beenthere]

Hard to justify a 1 ton increase, if it came out to 2 tons.

[Motortiger]

I'm getting a new quote with Trane 15i HP 2 1/2 ton it's not much more in price than 2 ton HP. But the saleguys says I need to go up a size in the air handler now because the coil is too small with the quote from the 2 ton. I think he said the new AHU will be dialed back 200 cfm . Does that make sense? He said the Trane air handers don't come in 1/2 sizes you have to go up to the 3ton AHU. That brings up the price even more. Do I really need it? I want it done right.

[beenthere]

Common for the ID unit to be rated the next 1/2 ton and some times full ton larger.
Its how they get the efficiency.

[Ed Janowiak]

There is an answer to whether or not to oversize up to 15 or 25%. ACCA manual H has the method to calculate how much you will save by increasing the size of the heat pump.

In my area, I have never calculated a heat pump that going up a size saved enough money to warrant a bigger unit. The heating savings were always very low.

If you're good with excel you can make a spread sheet for this (I'm not good with it, but have used one).

No need to guess, input the numbers and see for yourself.

[tigerdunes]

motortiger

Here is my first choice for a 2 1/2 ton XL15i Trane HP system.

1382160 Active OEM XL15I WEATHERTRON TRANE 4TWX5030A1 4TEE3F39A1 30000 13.00 15.75 30000 9.00 18000

full BTUs in both cooling and heating, 13 EER, and 9 HSPF eff for heating

2nd choice

1383563 Active OEM XL15I WEATHERTRON TRANE 4TWX5030A1 4TEE3F31B1 30000 12.30 14.50 30400 8.80 18200

numbers provided from the HVAC HP directory

Use a Honeywell VP IAQ stat.

IMO
:)

[Go Green HVAC]

The plumbing and Heating guy that is giving me the quote is one I got thru Home Depot. I thought Home Depot guarantees the quality of the contractor's work. My sister just told me there was a big thing in the news a while back of the Home Depot contractors doing shoddy work. Before I sign anything what's the best way to make sure they do quality good work. Should I be concerned here.

Many good companies shy away from the Home Depot program becasue the HD takes nice chunks off the top of the selling price. The sales guy gets his cut, the HD gets their cut. If the guy is still competitive with other local qualified HVAC guys, that would tell me the installing company, the actuall installers, the quality of work and all that jazz must be less than what the competion can provide. The overhead is simply higher.

All this chat about heat loss is amazing, even the pros here don't agree!! Tell me, when the sales rep says the ducts are too small for 3 tons of AC, yet is trying to sell a 3 ton HP, what in the wide world of sports am I missing here?

He did a heat loss for you, and he didn't show you the AC loads???? Huh! I wonder why. It could be becasue it's more like the two tons everyone here is going round and round about.

In this heat loss calculation, what does it show for the infiltration value? How did the sales rep come up with this number? I just doodled a 1200 sq ft ranch on my computer, and depending on whether I checked TIGHT or LOOSE, the number went from (this is heating) 34,000 to 41,000 BTUs. I'm always currious why many hvac guys swear by a heat loss report when they're just guessing at the thermal envelope and how tight it is. Find someone with a blower door if you want the real answers!

EWS? how come they're not listed on the Trane web site? do you get NATE certified technicians?

Hope it all works out-

GGHVAC

[Motortiger]

I want to thank Beenthere,Tigerdunes and others that posted on this thread, I went ahead and had EWS Plumbing & Heating of Monson Ma. do the install. I was concerned because of all the Home Depot shoddy work that was in the news a while back. But after checking with the Better Business Bureau and calling references I felt safe going with them. I took some before and after pictures that can be seen here http://mysite.verizon.net/vzez0koz/ I think they did a real nice job. They did more than I thought they were going to do. I didn't expect the condensate pump, digging out the old pad I'm sure was more work than they thought. The electrician did a real nice job too, he ran all new wires used existing holes in the wall and removed the old 10 gauge wires going to the old Heat pump and old metal conduit going to the AHU. The new Honeywell IAQ is very nice.

[tigerdunes]

Motortiger

What exactly did you wind up with, size mdl condenser, air handler,as well as size of heat strip?

and thus far,what is your initial impression?

td
:)

[beenthere]

Looks good.

[Motortiger]

I got the Trane 2 1/2 ton 15i with the 3TON 4TEE3F37A AHU. He didn't do heat strips. He said something about couldn't get it to work with the hot water coil. I didn't push it. He said the heat pump will run at the same time with the hot water coil. He said they did lower the max fan speed on the AHU. I think it's a little higher than before. I still have the fuzzy duct from when the house was built so I'm concerned about leaks. I would like to get new duct work in the future when I can afford it. Over all I'm very happy with the system. The heat pump has been heating the house in the cold mornings we have been having not the boiler. It's works good. The outside unit is very quiet.

[tigerdunes]

MotorTiger

You have made both an excellent choice on the Trane XL15i HP condenser and size.

From your pictures, the install looks very nice as well.

Not meaning to nitpik though, I don't quite understand the selection of the air handler. Here are the CEE HVAC performance numbers.

1383563 Active OEM XL15I WEATHERTRON TRANE 4TWX5030A1 4TEE3F31B1 30000 12.30 14.50 30400 8.80 18200 CEE Tier 1 HRCU-A-CB

1383565 Active OEM XL15I WEATHERTRON TRANE 4TWX5030A1 4TEE3F37B1 29400 12.50 14.75 30000 8.40 17400 Energy Star HRCU-A-CB


1382160 Active OEM XL15I WEATHERTRON TRANE 4TWX5030A1 4TEE3F39A1 30000 13.00 15.75 30000 9.00 18000

The 39 would have been my first choice, the 31 my second choice.

Not knowing your full set-up, I would ask dealer about the addition of a heat strip.

Why?
1.to handle the defrost mode.

2.to extend range of your heat pump at low temps and as a backup to your main source of heating.

TD
Best Regards
:)

[beenthere]

And why do you think he doesn't have full range with the hydro coil?

[beenthere]

Not knowing what area he is from.
Coil selection may have been made due to SHR required for his area.

There is a lot more to proper coil match up then you think. And that is why manufacturers have the different match ups.