Thanks for the compliment, as for the WHVDEH system, if we stay with split system, does that mean we would need 2 of these units or only need to install on upstairs system where humidity is higher and. Also if it matters, all the bedrooms are upstairs and living is downstairs, we also have a couple of large dogs that go out into the back yard quite a bit, letting in fresh air.
Designer Dan __ It's Not Rocket Science, But It is SCIENCE with Some Art. _ _ KEEP IT SIMPLE & SINCERE ___ __ www.mysimplifiedhvac.com ___ __ Define the Building Envelope & Perform a Detailed Load Calc: It's ALL About Windows & Make-up Air Requirements. Know Your Equipment Capabilities
The amount of tinting is measured as S OLAR H EAT G AIN C OEFFICIENT ( S.H.G.C.).
http://www.efficientwindows.org/shgc.cfm
CLEAR = 0.87
MEDIUM = 0.55
http://www.efficientwindows.org/glazing_.cfm?id=5
HEAVY < 0.30 may result in a Light Transmittance which provide such low outdoor lighting resulting in a "disturbingly dark" room even on a clear day
http://www.efficientwindows.org/city...dtype=WN&id=66
Designer Dan __ It's Not Rocket Science, But It is SCIENCE with Some Art. _ _ KEEP IT SIMPLE & SINCERE ___ __ www.mysimplifiedhvac.com ___ __ Define the Building Envelope & Perform a Detailed Load Calc: It's ALL About Windows & Make-up Air Requirements. Know Your Equipment Capabilities
If you live in the cold North, you need low-e windows that allow the winter solar heat to enter & then keep that interior radiated heat from passing back through the window pane.
On clear sunny days my furnace seldom cycles even on cold days; At 70-F indoors the design temp-difference I use is 83-F; Lacrosse, WI 99% Design is -13-F below zero. I have a 60,000-Btuh Input, 97% propane furnace that has no problem holding the design temp; - go-figure...
I only have two double pane low-e windows on the south side; one upstairs & one downstairs.
However, I have storm windows on all the other windows &, storms on the three doors.
Tight storm windows provide a u-value about equal to a double pane window at a fraction of the cost; of course they won't be low-e.
In my northern area replacing windows won't have a reasonable payback period, so in the North, look at all the other options before spending the big bucks, - unless your windows have to be replaced for other important reasons...
AOP Forum Rules:
Rules for Posting
Rules For Equipment Owners
Equipment Owners Find a Contractor HERE!
udarrell
Not knowing all ACTUAL window characterisitcs and infiltration, it's impossible sitting-over-here to make any definitive recommendation.
Rather inconsistent to provide 0.275 ACH on page 3 of PDF and not actually Use ~0.3 Infiltration Factor in the calc. (near bottom of page 4 = 0.6 / 0.8 Summer / Winter).
Also, it should be noted that 1st Man J calc used SHGC 0.52 which is a NOTICABLE window tint.
I don't credit shading by trees. Overhangs and porches make a measurable difference.
Designer Dan __ It's Not Rocket Science, But It is SCIENCE with Some Art. _ _ KEEP IT SIMPLE & SINCERE ___ __ www.mysimplifiedhvac.com ___ __ Define the Building Envelope & Perform a Detailed Load Calc: It's ALL About Windows & Make-up Air Requirements. Know Your Equipment Capabilities
I'm definitely biased to TWO systems.
Much more reliable long term given that contractors generally don't know how to install zoning systems.
AND there's a Slim_to_No chance that duct work ( headaches for lifetime) would be installed correctly in a house your size.
Use of too much flexible duct makes it impossible.!..!!
Designer Dan __ It's Not Rocket Science, But It is SCIENCE with Some Art. _ _ KEEP IT SIMPLE & SINCERE ___ __ www.mysimplifiedhvac.com ___ __ Define the Building Envelope & Perform a Detailed Load Calc: It's ALL About Windows & Make-up Air Requirements. Know Your Equipment Capabilities
4 ton Greenspeed, 2 zones. What a sweet setup to be able to go from 2 systems to one!! Baby have technological advances have served up dessert for you!
What's the blower door cfm50 #? - I bet every J used a different infiltration - did you give everyone the blower door number, or let some of them guess?
Guess I'm not alone in that thinking. Ideally you'll have the lowest stage be smaller than airflow requirements of the smallest zone.
+1
Nothing is forever. If you don't buy things for fear of unknown maintenance issues, how would you ever make a decision to buy anything? Allowing fear into your decision making process allows you to be manipulated, and results in some really bad decisions.
Maintenance issues happen to all equipment. Hack installers blame the equipment for their crappy design so MFR's get a bad rap.
Any ECM motor replacements being explained as:
"ECM burned up due to high static. Our crappy salesman sold you grossly oversized equipment, resulting in too much equipment on too little duct."?
No, it's: "We've been having a lot of problems with this crappy mfr's ECM motors."
Carrier system quoted is not the Greenspeed, see earlier post for model numbers.
Test results are attached to post 4 or 5 above. Going to provide results to other contractors.What's the blower door cfm50 #? - I bet every J used a different infiltration - did you give everyone the blower door number, or let some of them guess?
To clarify, install the whole house dehumidifier to supply filtered, fresh air via the a/c supply serving the isolated bedrooms with the dehu returm coming from the the open part of the home. This mix fresh dry air throughout the home, while needing only one dehumidifier. The Ultra-Aire 90H or 105H would be ideal. Opening doors is not adequate for the long peroids of time and calm winds that are most common in most green grass climates.
None of the VS a/cs are able to maintain <50%RH during times when the outdoor dew point is +60^F and the home is occupied.
Regards TB
Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
Use +Merv 10 air filter. -Don't forget the "Golden Rule"
2518cfm50. Wow! Tight house for it's age and size! Nice!
And some room for improvement, so if you have future comfort issues, air sealing efforts could pay off in spades.
4 ton Greenspeed.
With zoning, you might go 3 ton. Too bad we can't see run history on your current equipment, could parse actual load to confirm.
Awesome, someone is using Auditor! Did they true your actual annual consumption? I can't see it in the report and that is a nice triangulation point.
Elite. Can't see infiltration (reconcile to your actual cfm50) in the Elite report other than it looks like a big slice of your load, so it may be dead on or grossly overestimated. Also, looks like you don't have the duct to handle the 5t recommended BTU. Not terribly familiar with Elite, but I have a client in Baltimore whose Elite report has proven out to have been quite oversized in it's recommendation. I think it recommended 4 ton, he put in 2, and has been very happy. And the East Coast had a very hot summer.
A lot of people come here looking for confirmation of bad emotionally derived decisions they've already made. Often it's to justify not spending a small incremental cost that when amortized over the life of the equipment, and reduced by the incremental energy savings and dramatic increase in comfort and control often has a $0 net added cost. When it goes bad this ends up being money that they really wish they'd spent up front.
Yes, I see they didn't spec Greenspeed. Whose mistake is that? Did you come here looking for advice from experts? You seem to be dismissing the advice of a number of folks. You are buying surgery and have some choices. Become a surgeon, or accept that what other surgeons are saying may have merit that is beyond your depth. I don't know what you do for a living, but I certainly wouldn't expect to be qualified to understand it after a week or two, do you think you somehow have what we do all figured out? There is a very complicated critical path here with a lot of potential failure points. If you are stepping into communicating zoning, with that duct, particularly with 4 ton, I think you'll want the Greenspeed.
We do see the results of a lot of bad decisions on this BB, fear, oversize, and short sighted focus on up front cost account for most of that pie. We have NO skin in the game of your decision, you have to live with it.
The guys selling to you will confirm whatever they think will make you comfortable enough to sign the contract. The incremental commission on better equipment does NOT matter to them, it is VERY small. They want the SALE. Whatever you will buy, they are happy to sell you because that's how they feed their families. That's not a judgement of good or bad, right or wrong, it's simply what sales is.
Last edited by tedkidd; 10-14-2012 at 03:10 PM.
While I live and practice heating and AC in the Atlanta area, I grew up and learned the trade on the Texas gulf coast (Houston, one of the hottest and most humid places in the USA).
First: Load calculations are NOT totally accurate to minute details, there are too many variables involved which are judgement calls of the person doing the calculation.
Second: This is one of the benefits of VS drive furnaces, they take up a small amount of slack.
Now I know folks are about to pounce on me and fuss about the two statements above... however before you do consider this:
Sizing equipment (and ductwork) is based on the heat gain and heat loss of a structure... however at what indoor and what outdoor temperature and RH (relative humidity)? And of course we have the infiltration issue, the BD test will help to determine this factor.
On a mild day in swing season, one needs a considerable amount LESS heat capacity or cooling capacity than on an extreme day... yet we fuss about 1/2 ton (in this case something like 10-15%) of capacity. A VS drive furnace PROPERLY matched to the coil and AC unit and PROPERLY installed (those two factors are WAAAY more important that whether it is 3.5 or 4 tons). Same issue with heat capacity size; not worht fussing over. Note: In an AC market (like Florida), the furnace size is based on airflow capacity for AC, not for heating capacity.
It is easy to play the 'numbers game'... however if someone does not understand WHAT the numbers mean and WHY they are what they are... it is just that, a numbers game.
Advise to homeowners: Hire the person who you think understand what they are doing and will do their best.... DO NOT try to understand what they are doing (and tell them how to do it). That is the BEST WAY I know of to get mediocre value for your $$$ when replacing your heating and AC system.
One would not tell a dentist how to do a root canal and crown... one would not tell a surgeon how to do a bypass... Well do not try to tell heating and AC contractors how to do their job.
If a HO does not think the contractor is a professional... then do not hire them; find someone you believe IS a professional.
OK... lets see where this goes...
GA-HVAC-Tech
Your comfort, Your way, Everyday!
GA's basic rules of home heating and AC upgrades:
*Installation is more important than the brand of equipment
*The duct system keeps the house comfortable; the equipment only heats and cools (and dehumidifies)
*The value of comfort, over the long term; leave economic choices behind!
Choose your contractor wisely!
Sorry but I don't see where I am dismissing the advice of anyone here. Just trying to learn more and even here the recommendations are different, in fact I would say split on the recommendation for a single system vs. 2 systems. Even your recommendations differ from those who have actually been in the house, you say go 4 ton or even 3 ton, yet the only contractor that made the recommendation to go with a single system says 5 ton is necessary.
For me the mistake is with the expert who is making the recommendation. How is an HVAC layman suppose to know what is best suited for a particular application.Yes, I see they didn't spec Greenspeed. Whose mistake is that? Did you come here looking for advice from experts?
Exactly which is why I am trying to gather as much info on the benefits of one system vs. 2, and to be frank I haven't really see anything compelling by going with a single system, ie. comfort, reliability, air quality, savings, etc.We do see the results of a lot of bad decisions on this BB, fear, oversize, and short sighted focus on up front cost account for most of that pie. We have NO skin in the game of your decision, you have to live with it.
Easier said then done.
Yes, I agree!
When I go to find a Dentist, Eye Doc, etc... I have to decide (and rather quickly mind you) whether the doc is someone I can trust or not.
Us HVAC folks generally do 3-4 years of trade school, then anywhere from 4-6 years of OJT training before we are allowed to be licensed.
Then we have to do endless Continuing Ed classes as well as keep up with a changing industry.
We are indeed professionals... the only problem is we do not always represent ourselves as such.
Find a TRUE professional, someone that really enjoys what they do and truly does the BEST they can with each job. You will get your $$$ worth with that person.
GA-HVAC-Tech
Your comfort, Your way, Everyday!
GA's basic rules of home heating and AC upgrades:
*Installation is more important than the brand of equipment
*The duct system keeps the house comfortable; the equipment only heats and cools (and dehumidifies)
*The value of comfort, over the long term; leave economic choices behind!
Choose your contractor wisely!
Excellent! You are clearly on board now. (And quite frankly, you've already done more due diligence than 95% of homeowners, chances of making a mistake were looking pretty slim.)
Next step is settle on your specifications. If Carrier, I think not selecting Greenspeed will prove to be a big mistake. Whatever mfr, looks like you already are convinced top of the line 2 stage minimum makes sense.
You can take it to bid if you like, or simply chose the contractor you feel most confident in. Most markets pricing is fairly competitive, so your potential for savings often doesn't justify the effort of shopping.
Keep in mind you may want to be thorough in your vetting process. Because you have confidence in the guy selling doesn't mean he has any control over how things go in. You may want to talk to clients they've installed high end equipment for, even look at the installs.
And a satisfaction guarantee that is more than verbal, particularly as you get into more complex jobs, should be much more important than saving a few hundred dollars. (Remember, 100 dollars over 15 years is about 2 cents a day.) Someone mentioned spending the money on 10 year parts AND labor, that's probably money well spent.
What is it about Greenspeed that is magic? Having tested one for a spring and summer, I was impressed with it's avoiding a few on/offs each day during medium cooling loads. But the home's lower level was cool even with supplies off and +60% RH, needing supplemental dehumidification to maintain <50%RH. Also at the very low speed cooling rates, the low air flow did not provide good circulation throughout the home. The system overcooled 3^F, which the occupants found annoying. Yet the entire house was +60%RH during low/no cooling load conditions. The system is 2X more expensive than a VS blow/medium seer a/c. After initial setup, maintaince and service will reqire the best techs and be pricey because of the cost of the components. Some of the components cost as much as simple a/cs.
If you want the best, regardless OK. But plan on including a whole house dehu to provide fresh air ventilation and <50%RH when the outdoor dew points are +55^F, with moisture from the occupants, and low/no cooling loads.
My past post show the data, or if you want specific data, request the condition. If pure magic is claimed get it in writing. It is pricey.
Regards TB
Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
Use +Merv 10 air filter. -Don't forget the "Golden Rule"
Gotta agree with the Bear. I've been to 2 coarses on the Greenspeed and I'm not really impressed with it. I see extreme down the road costs and problems with PMs on it. You will either have to pay more for your PM or get half a$$ PM which will cost you big $$ to correct. Alot of thought and engineering went into and on paper it looks fantastic. Just don't see the potential minimal gain in efficiency worth the cost or the risk. It is a very complex unit with alot of stuff that frankly is over the heads of most residential techs and most likely all younger new techs that typically will be doing the PMs. That's what my 24 years field experience tells me any way.
Two very good counter points that should be considered. Those issues mean net cost analysis, Greenspeed probably will be more. Guess it depends how much heating cost savings there are in that big COP jump.
He'll probably not be putting in one much less two Greenspeeds, but without them in the cost/benefit analysis, the decision matrix is incomplete and biased. Poor or biased perspective leads to bad decisionmaking. If it were my audit I'd be modelling them to understand net cost.
TB - Infinity allows scheduling fan settings. Try managing fan settings seasonally.But the home's lower level was cool even with supplies off and +60% RH,
My mother complained of icebox basement as well. We found that if she turns her fan to "On Medium" in April, then back to auto in July it seems to solve her icebox basement problem. I think she subsequently has gone to "On Low" the rest of the year, it keeps parts of the house from getting stale and dramatically cut dusting.
The idea was that by improving air circulation/mixing through the house during the period equipment otherwise seldom runs, and that the ground is coldest (pulling a lot of BTU from the basement that aren't being replaced), it evens temperatures throughout and you actually gain some cooling benefit to the rest of the house from the cold mass.
This assumes you have a low return in the basement, you want return pulling from the coldest location (hopefully Brian won't see this).