New Addition questions

[toocoolforschool]

I have a 1.5 ton now and it can't keep my existing 750 sq ft cool when it's 95 outside. Roughly 400 sq ft of that is over an unconditioned garage.

I f I had a nickle for everytime I heard that one. Unconditioned garage will increase heat load. You should look into a whisper quite unit if noise is a concern. Two stage condenser to handle extra load requirment like lots of family or electronics, this does not sound like a builder grade application.

[Shophound]

I believe it's an equipment issue.

May I ask what you base that on?

Far too easy to blame the equipment when little attention has been paid to the building envelope. It's not all about just keeping the air cool and dry. Your surroundings need to be cool as well, or you won't feel comfortable.

Other pro responders here have already advised you to not proceed without a load calculation. I add my voice to that. Anyone who comes to your home and just "eyeballs" a guess for what you need is wasting your time, and can become an expensive mistake if you go with someone like that. Same for someone who says "oh let's just add a return here and throw a few supply registers around, everything will be cool!" No, it probably will not.

Since you intend a home theater for the addition, you need to step up the quality of those you bring in to consult on this project. Big time.

[wraunch]

How can I check the envelope of the building? When I walk in my attic it is typically 15-20 degrees warmer than outside in the summer.

[wraunch]

I had a company come out and recommend a Trane solution that was approx $3K more than the similar solution from American Standard. The guys I had out today use American Standard, they also mentioned that they typically use baffles and they need to do load calcs, etc. to really price it out. I liked their attention to detail much more than the guy yesterday.

[mechanical'al]

your 1.5 ton system may have some isues as it should not have any trouble cooling that space

[jtrammel]

The reason it won't keep up is probably because your duct work leaks and is pulling in hot attic air through the return and through leaks in the building envelope. It could also not be working properly as well (low refrigerant, low airflow etc.)

[wraunch]

Ok I've got two final bids. One is a Lennox dealer the other does American Standard. Both calculated the loads at 2.5 tons. The Lennox recommendation is a 15 SEER Xp14-030 Elite Heat Pump with a CBX27UH Air handler and a CS5000 Tstat for $$$ after the local power company rebates. They recommend we zone the new unit, place a return in the theater and a return in the new bedroom. They also recommend increasing the size of the some of the existing ductwork as it is six inch and should have been larger. Also, the Lennox contractor is telling me the variable speed air handler isn't necessary since I will have all ceiling vents. Is that true?

The American standard quote I am getting is as follows: 14 SEER Heat Pump (don't have model #) and the GAM air handler with electronic expansion valve which increases it to 15 SEER (that's what I'm told). That would be $$$ and if I want it zoned it would be another $$$. I think that is probably going to be well worth the money to have it zoned.

Which solution should I go with?

[jpsmith1cm]

wraunch

pricing isn't permitted here.

[jtrammel]

Yes supply and return ductwork definitely needs to be larger to add another ton. I don't know what he's talking about with the variable speed not necessary bc of ceiling registers but no it isn't necessary just will give a little better seer rating to the matched system and more versatility in airflow options. Zoning may or may not benefit you for the added expense, with the unit being single stage I don't see it helping anything too much, without seeing the application I can't be sure though. 2.5 tons for ~1500sqft sounds awfully similar to the old rule of thumb 500sqft/ton.

[wraunch]

Sorry, let's just say both options are the same price. The only difference is the Lennox contractor seems to have a little bit more professional business.

[wraunch]

I think zoning is necessary because half of the upstairs is a bedroom, bath abd game room over my garage and a few downstairs bedrooms. The remainder will be an 18x30' theater that will have 4 doors around the room that all will have weatherstripped thresholds and an additional bedroom.

[wraunch]

Here is the floor plan for my upstairs.

Here is the floor plan for the new addition. All of the doors will be either exterior, weatherstripped doors or interior, solid core, weatherstipped doors with soundproof door sweeps.

[dan sw fl]

Quite a PROfe$$ional theatre.
________. _ _ How much will admi$$ion be?

[wraunch]

Yeah it's been a dream of mine for 20 yrs to have my own dedicated theater. I'm doing most of the work myself and subbing out some of the bigger trade jobs like electrical and HVAC. I'll probably have $10-15k in the construction and another $5-8k in equip.

[wraunch]

Any other guidance? I will probably look to get this installed in February.

[mechanical'al]

when we are telling u to have a load calc. done! it truly means they must do a manual j or computer equilivelnt not just to look and give an opinion