We are about to begin building a new home and a home recording studio that will be above the detached garage and I thought I’d ask a few questions here, I’d appreciate any suggestions you folks my have.
First off I have a general contractor for the project, he has given me a couple of companies he works with for HVAC but with our agreement, I can look at other options and so I would like to get some information to make a reasonable bid form.
The house is about 3800 sq ft craftsman style, 2500 Sq ft bottom floor and about 1800 sq ft upper floor. The house will have quality energy efficient wood clad windows with Low E and Argon throughout.. the design is wood frame, with rock and brick exterior. 2x4 walls, standard insulation exterior walls and under raised floor, I’m thinking R38 in the attic. Right now the contractor said I would probably need a 5 ton down, single unit and 3 ton split system up. The studio over the garage will be either a 2 or 2 ½ ton unit (similar to another studio I had)
We are leaning to a dual fuel heat pump with propane gas system, the house were in now has a heat pump and on cold nights it just does not heat like were use to, so we turn on the aux gas and it gets toasty warm n those nights.. so, I think for us, the dual fuel will be our choice for all the systems. (one exception may be is on the studio to use a electric backup rather than gas just because of the gas line run).
Our contractor gave us a budget, but of course, he used pricing for a single heat, heat pump, 10 SEER for all the systems, and I really don’t think that is what we want. Given the move in date of this house probably wont be until the first couple months of Jan 2006 the new specs will be 13 seer, so, I think I want to go to at least that level unless you guys tell me different! I know it sounds crazy, but I’d like to find a good Price/performance point for the project and I know one can spend lots of money chasing efficiency and never realize the pay back.
Our past two homes out west one used the Rheem system, and the other Trane.. fortunately we didn’t have any problems with either home, both continued to work well and the last home, we were in the home for 14 years with out a service call!
The contractors that our builders work with offer Trane mainly, there is an American Standard dealer locally and not to far away a Lennox dealer.. so all seem quite well known for their products..
The Nashville area has hot and humid summers, and the winters are quite mild, although this year we have seen some 10 degree weather and quite a few evening below 30 degrees which at that point, I turn on the gas Aux (or it comes on by itself.. being use to Gas Heat.. the heat pump just doesn’t t cut it on it’s own). I also am looking for “Quiet Units” I hate to hear AC units craning away all the time. Our Lennox systems were pretty quiet.
So, I guess what I am asking is, am I going in the right direction to go to the 13 seer? What kind of premium over 10 seer will it cost, and then add to that, dual fuel, I am really thinking I’m going to get quite a shock over the standard 10 seer system the contractor gave us a budget for.. but will the upgrade be worth the cost?
And am I on the right track with Trane, American Standard and Lennox names? Are there ones I should cross off the list and or add?
The studio application will have other issues on supply lines, lengths of duct work and large supply and returns to keep the noise to a minimum.. I realize this will be special and cost additional over the standard installation.
Finally.. I am interested I addressing the Energy Star program through the local utility Company Middle Tennessee Electric, they have some stringent install requirements that most installer will cost me more than the rebates.. any comments? Is it worth it?
I know this is a lot of questions , and I do appreciate any replies from you professionals I’d rather be armed with information than to walk through these decisions blind.
If you would like email me replies to firstname.lastname@example.org if you have a number that I can call you at let me know, I’ll call on my nickel..
Again, thanks. Dave Kirkey
What's the cost per kwh of electricity and cost per gallon of propane? I'd bet keeping propane out of it would be much cheaper.
If the contractor thinks 5 ton for 2500 sq ft 1st floor, he must build horrible homes. I'd think 1/2 that. Unless you want humidity problems, somebody better do a very accurate heat gain calculation
A-S/Trane or Lennox would be fine, just don't buy a builder model from either brand.
humidity, humidity,humidity, did I say humidity?
vapor barrier, if any to be on INSIDE of walls -- read BUILDINGSCIENCE.com.
designing for high heat loads in a single room takes special design.
designing for a quiet room with high heat loads takes even more talent. but such should be available in Nashville!
I would put spray in Soybean based foam insulation in walls covered inside & out with Styrofoam which must be covered with 0.5" tk gyp. Then spend some $$$ for sound capturing devices at each ceiling corner! -- lots of drapes & carpet & ...
BTW, $0.056/kwh here in Huntsville AL -- TVA + city util.
The sizes were not from HVAC guy yet
Thanks for the information, Geeze, maybe I got a step ahead of myself, and I am sorry I did, I have not sat down with a HVAC guy yet, the contractor just did an estimate on costs and kind of thew out some sizes but I may have been wrong with the sizes.. sorry... Your are right, I do need to sit down with the HVAC guys to go over the house and sizes and hopefully I'll get to that his week...
The cost of electric here in our area is .066 per KW, so fairly cheap. Propane, well if I buy in summer it was about $1.00 to 1.10 per gallon, I'd put up a 1,000 gal tank that would hopefully take me through the winter high cost months..
Does that help? (and yes, the house is going to be tight, and energy efficent windows)
You need to find a third party consultant in your area that helps design energy effecient homes. Check your utility company for this information. You need someone to build the thermal envelope correctly, do a room by room heat gain/loss analysis, and integrate a single, zoned HVAC systen with ducts in the thermal envelope. If you depend on your builder or HVAC contractor you are in trouble!!!
Cem-bsee--Vapor barriers (less than 1 perm) should never be used in his climate. Only semi-permeable vapor retarders should be used.
[Edited by uktra on 02-06-2005 at 11:21 AM]
Just on backup, straight resistance is $19.34 for a million BTUs. Propane is $15.26 with an 80% furnace so a slight savings with propane. Personally I'd skip the dual fuel and just go all electric anyway. Running the heat pump colder will make up the few bucks savings of the propane anyway and cost less to install and less to go wrong. My personal opinion.
Thanks again for all the input!
I agree, a pro HVAC guy is needed and that Is what I am going to do, I am sure that is what the contractor would want as well, he has given me a few guys that he works with all the time as well as I'm looking in to others. I should have a set of plans that make sense in about a week or so, that way I can sit down with 2 or 3 HVAC companies and see what they offer.
I am going to explore the costs of straight electric vs. dual fuel, your right, the simpler the better, even if the Eletric could cost us a little more from time to time, I need to find out what the premium dual fuel system will cost me. The Electricity here in the Nashville are is quite low, and the price of propane is quite high, I just need to find out what the difference in dual fuel ves straight electric will be and make my decession..
Keep the comments and suggestions coming, I realy appreciate the input.
this is just my opinion i do not think i know it all so just leave it at that, 2500 sq foot will be close to a 5 ton and in know way will 2 1/2 tons be enough in tenn.That would equal 1000 sq foot per ton.
Filterchanger--You cannot design HVAC capacity by sq. ft. I have helped design homes that work in the same climate as Tenn. at over 1500 sq. ft. per ton. It all depends on how you design and build the home.
Yea your right but in most homes a 1000 sq foot per ton is just not gonna cut it,I know you cant size equipment by square feet.
perhaps, a little more info can help this discussion.
The home is a Craftsman style, with a raised foundation, hopefully we will have a good crawl space of 2 - 3 feet.. the construction is wood frame, 2x4 design, r 13 outer wall insullation, all voids sealed and filled (actually the contractor is very good about this), the outer design will be about 1/3rd up will be rock with Brick up from there. No siding what so ever, its all either brick or rock all the way. the windows will either be the top of the line Pella insulated, low e with argon gas, Wood - aluminum clad windows, (not home depot, but pella direct) doors will be all sealed tight dual insullated doors (french doors will be insulated glass) full insullation under the house and I am shooting for R38 in the attic areas. I am using 5/8" drywall instead of 1/2 inch just because I like the solid feel and our last 2 homes have been 5/8 inch.
I am confident in the contractor, we have seen many homes he has built, so, his construction methiods are top notch (matter of fact, most subs tell us he is the pickiest builder to work for in the area) he builds each home as if it were his own.
The only thing we are dealing with is the heat pump issue at colder than 40 degrees.. the current home as I mentioned when the thermostat is set to 68 and the Aux gas is not kicked in the house feels cold, but I kick up to 72, the aux gas (propane) kicks in and were tosty warm..
My big questions had to do with equiptment, Standard Heat and Air Electric, Heat pump system with out a dual fuel system and then a heat pump system with dual fuel with the fuel being propane.. I probably should have not brought up the size at all, that was my mistake., sorry!
And, Im not asking for specific prices but the trade offs of 10 seer, vs 12 vs 14 seer units with the above characteristis..
If I were to use a 10 seer all electric as a base line what would the 12 or 14 run as a percentage increase.. then, add to that dual fuel.. there has to be a way to get an idea.. like 10% more, 20% more or what.. where is the break even point, we plan to be in this home for quite sometime, our last place we were in for 14 years.. and as I said that was a lennox system from 1991 Electric Air, Natural gas heat..
I hope this helps a little more..
Your builder using fiberglass or cellulose in walls? Foam board on outside of walls? Sealed and conditioned crawlspace? Sealing sill plate/base plates? sealing frame? Penetrations? Sealing windows with foam? Keeping ducts inside thermal envelope?
There is a big difference between code built and energy efficient!
Back to sizing, 2500 sq ft on the first floor with most of the ceiling covered by conditioned space is going to need far less cooling than 2500 sq ft with attic above it. That's why I couldn't fathom 5 tons of cooling for that area with mostly walls for heat gain.
With a good digital stat, I think you'll find all electric plenty comfy. They are quick to bring on backup if the temp drops. Honeywell quickly cycles its backup to avoid wild temp swings which can cause discomfort. A high SEER heat pump with scroll compressor tends to put out warmer air than lower efficiency recip bearing equipment so today's better units heat better than the older units.
Have you looked into foaming the place instead of batts & blowing insulation? That will turn your house into a fortress. Infiltration will be nil.