help in undersanding energy efficient issues

[berad]

I may have mispoke, I realy can't accuratley comment on the size without personaly running a load calculation either from a print or in person. What I can do is based on your specified size and heating hours and cooling hours and kw/hr. I can give you an estimate on energy usage. I have lost track throught the post though. Are these heatpumps, dual fuel heat pumps, or gas heat plus a/c systems? and if anyone knows the degree hours this will be helpful, I can't find my map that shows each area's hours of operation.

[davidki]

All units will be heat pumps, the down stairs one will be a dual fuel, electric/propane design Like I said before, the first design ws with a package unit but now were going to a split system down also. The upstairs units will be heat pump but no gas.. hope that helps. I appreciate your help, I have the plans scanned in and can email them but I am not sure if you will.. let me know.

Dave

[berad]

Downstairs is a 5 ton dual fuel system, upstairs is 2 ton heatpump, studio is 2 1/2 ton heat pump is this correct? I am currently looking for my degree days map, should be able to give you energy usage info tommorrow. I can run a load if you like, my email is: berad@mchsi.com

[davidki]

Down stairs is the proposed 5 ton heat pump, dual fuel split system, the upstairs of the house is the 2 1/2ton split system and then the studio is the 2 ton system.

Like I said before, I like the variable speed air handlers that are available on the market.. looking at the trane systems they have a standard single speed handler and then the upgraded variable speed.

I know I am going to upgrade from the "Builder Model" units and it will be interesting to see what the calcs come up with on seer's. I can list the equiptment that is proposed if necessary as well.

One of the oontractors (the one my contractor likes best) is strictly a Trane guy.. the other offers American Standard, Carrier and Goodman. I am not really looking at Goodman to put in, I had one in my last studio and the control board fried in 2 years.. were very rude to deal with!

So, hope this all helps. Like I said,I'd be glad to give you a call, I really enjoy learning as much as I can on this and if talking on the phone makes sense let me know how to contact you.

Dave

[davidki]

Sorry, I was not specific enough. All the systems will be heat pumps, the upper floor and the studio will have electric heaters not gas..
Dave

[dash]

Your contractor may be basing the system size,more on the heating needs ,than the cooling.

In a very dry climate ,I've heard of this being done,larger system,less need for backup gas or electric.

However ,in a humid summer climate ,the cooling will be oversized,and indoor humidity will be too high and uncomfortable.Can also contribute to the growth of mold.

When you ask about the loads,see if it's being sized for heating or cooling.

He also could be unaware of the type windows being installed,and used a more standard in the calculation.

[davidki]

In our original quote we were using a package dual fuel system (trane 1200), but now, we have decided to go to a split system, so, does that mean my dual fuel system is out? I am not sure if now the air handler has a gas heater side. I don't really want to go all electric on the 5 ton, I'd still like to have a dual fuel aproach, can I?

[dash]

You can,if the location of the furnace allows proper venting,etc..

[davidki]

Thanks for the reply, I will make sure the HVAC guy knows about the windows.. Hey, if I can reduce size, great, less cost to buy, less cost to run. I will get with them perhaps this week and discuss the loads..

I did mention to the HVAC guy that for the downstairs I'd rather have more heat so that is why we went to a dual fuel option, this house has it ,and it's nice when needed, although, who knows, perhpas the heat pumps today can actually heat enough with out the gas, but when the temps really get down (this year to 9degrees) it will be nice to have a back up..

I'll mention the potential over size of the air concern, that was an excellent point about humidity.

We moved here in May from Southern California, so, the weather is completely different than what were use to for sure..

Dave

[berad]

Ok, here goes nothing! I started another thread toget the operating hours. I don't work on heatpumps much, I'm farther North. I'm going to assume 50/50 operation between back up heat and heatpump. starting with the cooling at $.06/kwhr and 1616 operating hours per cooling season. The 5 ton 10 seer will cost approximately $582. per cooling season, 5 ton 12 seer approx. $485. per cooling season, 5 ton 14 seer approx. $412. per cooloing season. Now for heating I'm assuming 100,000 btuh furnace for the backup heat on this unit, operating for half of the 3729 heating hours and $1.10/therm of gas. An 80% furnace will cost you approx. $2033. for it's share of the heating load. I have to say though, that seems like to many heating hours for your area, but that's info I've been given and it will give some base of comparison. Anyway, 90% furnace with the same parameters will be approx.$1797.Now for the heatpump portion of the heating cost, again at $.06/kwh and half of 3729 heating hours. 5 ton 10 seer $671. 5 ton 12 seer $560. 5 ton 14 seer $475. This is the info for the first system. As I pointed out I don't think you have tht many heating hours, that is more than I have in central Illinois, and you're gas rate may be different and the balance point of the heat pump is closer to 70/30 rather 50/50 from what I can ascertain. Again, I apologize, I'm not a heatpump guy, very few of them in my neck of the woods.

[berad]

Now for the 2 1/2 ton system with strip heat backup. Under the same parameters as before. 10 seer for cooling $291. 12 seer for cooling $243. 14 seer for cooling 206. The electric back up will be the same parameters of a 50/50 split. Assuming 10 kw heating the back up will cost you approx. $1120. The heat pump side for heating will be as follows, 10 seer for heating $336. 12 seer for heating $280. 14 seer for heating $238. And the smaller systems numbers will be marginaly smaller than these but equal in proportion. I know this exercise wasn't very precise, My numbers are much closer when dealing with split system a/c and gas heat in my own area where I am familiar and informed, but I hope it gives some basis for your comparison.

[davidki]

I really appreciate the work you put in to this, I did see the thread on the heat and cooling days, and I did go to the site via the link. Im not sure how thoes numbers get calculated either.

Now for a couple of stupid questions.

1. The "Season" use, is that the total amount based on the numbers from the chart and do I assume that would be for per year? (not per month)?

2. from what I have seen in this house the secondary gas hardly kicks in at all unless we get below 30 degrees and that would also depend if I tweek the thermostat a little warmer. Your probabaly pretty close on the cost of fuel, I think we probably average $1.10 per gallon here recently. I know that at times it is quite a bit higher but we can get a level pay plan that would probably averate the $1.10 costs.

It seems pretty consitant the savings are about 30% from the 10 to the 14 seer which seems pretty good, even better than the Mfg specs, but, its still minimal overall vs. the cost of the upgrade (ok Im not going to get in to the price issues).

It will be intersting to see what our electric bills end up once we get in.

With the new specs for the EPA going to 13 this coming year it will be interesting to see if the units get more competitive as more units get changed over. I'd probably be happy with a 12 SEER, or possibly a 13 seer unit just to be up with the EPA.

Now given your comments about the heat pumps, I wonder if anyone else will chime in on the figures on heat pumps.

I really appreciate all the work you have done, if your ever in the Nashville area I deffinetly owe you a lunch.. thanks so much for taking your time and taking the effort to provide me with some numbers to work on..

Dave

[cem-bsee]

again, humidity

save $$$, let inside drift to 80F, if 96F+ outside

read at BUILDINGSCIENCE.com about good house construction!

[davidki]

I have gone to BUILDINGSCIENCE.com and checked it out, some of the information is quite interesting and I am allways looking for more refference ...

I spoke with our contractor today, he is going to talk to the HVAC guy and see if we can get more details regarding the design and equiptment... I'm sure we will get it all figured out..

[41gasman]

DavivkI.
Sorry I have been out for a while And misted a lot of your and others post on your problem.As a simple idea you could go up to the top of this page and hit the bulls eye.There you will find the Hvac-Cala program that is offered here for a free trial run.It is a pretty damm good load calc program that is relitively easy to use.You me and people like us have a bad case of the I JUST GOT TO KNOW thing.
First off It will blow your mind.Because it lets you see with and play with some very powerful information about you heating and cooling needs.And you get to change all the what if to see if THAT would be a good idea or not.The one thing it will also give you is the heating and cooling days for your area.That the info you need to get the answer to the HOW MUCH that you have had such a hard time finding.
I will tell you that the one thing that you can do that will save you a lot of money and increase your comfort level.Is to seal the living snot!!!! Out of the duct work.
This means with mastic and the plastic mesh.The mesh looks alot like the stuff you see for the seams in wallboard.Do not use chases for any return air.Hard pipe it all.When you get done with the sealing part insulate the SNOTT!!!!Out of it.If they use flex ducting for anything than besure to use at least a R-8 insulation.From what I have read here they use a lot of R-4 or R-6.Why I don'tknow.As I tell all my customers"Insulation is your friend.It cost you one time and then pays you back forever!!!!".
Good luck.One more thing even if you go with the lower seers.Wich I thing you will find to be the best bang for your buck.Get the V/S motors.THey are worth the money .They help eminsly(spelling)with your comfort.Dehumidification.
And than you can use ths fans to filter the air twenty four seven very cheaply.Make sure you get at least the four inch filters and filter racks!
41Gasman

[davidki]

Thanks, I did down load the trial version of the SW but have not had the time to run it yet, I'll have to give ita look. Also, Thanks for the info on the Insullation. I hope that I can sit dwn with our HVAC guy and have a good discussion about all this and yes, I am looking at the VS air handler.

I did have a discussion with our contractor today as well, he thinks as I do that teh 13 Seer systems may be become more competitive once the EPA restriction goes in to effect. I'm still about 10 weeks from Rough in, so I have time to continue my discussions..

Again, thanks for your input! Dave

[berad]

The rough cost estimates were based on the heating and cooling hours off of the other thread. The dollar amounts of usage were per season. Like $300 cooling meant to run that unit for the entire a/c season would cost a grand total of $300 and I appreciate your lunch offer. Espeacialy since the only thing I can verify as accurate are the cooling numbers, and that's only if I have the right cooling hours. All of the calculations were made from an energy star cost calculator I have that breaks it all down into math equations. Just plug in the numbers and use the slide calcultor and there are the numbers, but it is intended for gas, and oil heat and straight a/c. That is where I used what I had to create a parameter and calculate the rough numbers I had based on the real numbers I had from the calculator.

[davidki]

Well, thanks for your help, what it did do is use a set of control numbers and assumptions equally on each unit, and then with 10, 12 and 14 seer and it did give us an estimate of base line (10 seer) to the uper level of 14 seer.. that's enough information for me, What it did show is based on those numbers the difference from 10 to 14 seer was about 30% based on the same hours of opperation. It will be interesting to see if our HVAC guy is willing to do the same with what software he has and base it on our rooms and lay out. REading alot of these posts, and the various marketing info the Variable speed fans seem like a good idea, so, maybe I can come up with a nice mix of Seer and price and have a very comfortable house.

So, if your in Nashville, you will have to let me know. Thanks again for your help and taking the time to work on this for us.

DAve

[davidki]

I just found a site that gives the gas heating days for the region, here is the site http://www.findarticles.com/p/articl...3/ai_103994964 from what it shows it is an average of about 447 Gas Home Customer-Weighted Heating Degree-Days Seems like this is for Gas vs. propane but could offer another look at the number of days? You mentioned you thought the numbers you had before were high, this may be a little closer to what you were looking for?

DAve

[davidki]

Just found this government site it has up to day heating days info.. check it out.

http://www.eia.doe.gov/emeu/mer/pdf/pages/sec1_18.pdf