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ojs2005

Help - HVAC Sizing Issue and Variable Speed?

ojs2005
14 years ago

Can you tell me if this sounds right -- i have a large victorian -- about 1800 sq ft per floor with 3 floors (not including basement). We have very large 1 pane windows and the house is not insulated (we will probably insulate this year, but the windows are another story). My contractor's HVAC person has recommended installing Rheem equipment -4 ton condensers and 4 tons coils (13 SEER) with 5 ton drives for the AC, and 100,000 BTU furnaces -- for EACH floor. which would mean i have 12 tons of cooling in my house. we plan on putting a couple of ducts to the basement for cooling purposes but it has separate heating and we don't want to spend much money in the basement right now. They are telling me that this is the right size and not to spend more on variable speed higher efficiency units.

This is around the range of what other people offered, some thought more tonage, some thought less. One ocntracter suggested 3, 3.5 and 4 ton units for each floor respectively and said this was based on J Manual calculation. They also suggested about 85,000 BTU heating per floor -- but their price was almost double so I wouldn't even consider using them.

This is making my head spin. Does this sound right? Does it really make a big difference to have variable speed units (which I was told would cost about $12,000 more than our current quote to install in order to upgrade all the equipment and additional labor costs)?

I just don't want to spend all this money and have a house that's not comfortable because the A/C is oversized or uncomfortable.

Any thoughts would be MOST appreciated.

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