Upgrade Decisions

[Driverfound]

Hi,
I just moved into an 800 square foot condominium with a Rheem downflow gas furnace and A/C combination. My question is whether I should get some quotes to upgrade to a newer 90+ furnace, or stick with what I have for a few more years. The Rheem will be 20 years old this year, but is in great condition, and has been impeccably maintained by a professional (I know this because my Grandfather lived here before me). The A/C on the other hand definitely needs a new condensing unit, and probably a coil. Also, does anyone know about what the efficiency of my current furnace may be? It is natural draft with HSI.
Thanks!
-Mike

[joekent]

I would suggest you have the unit looked at depending on your finances. Upgrading is a good Idea as the efficiency of newer models will drastically reduce your heating and cooling costs. Hope you find this usefull. I would suggest also that you go with at least a 13 seer for AC. R-22 still a good choice and more affordable than 410.

[motoguy128]

If the current furnace has an HSI, it's likely a 80% unit. With such a small home, you may struggle to get a payback on a 95% unit...except that the tax credits cover the increased costs. So it might be a good time to get a matching system.

The 95% units are almost all Vairable speed are 2 stage, so you'll get added comfort in more mild weather.

Since your cooling season is realatively short, you might not get much payback on the A/C so I'd try and save some money there and just go with a basic 13 SEER unit (lowest now sold). You'll still save 30-40% on your cooling bills compared ot a 20 year old system that's probably around 8 SEER.


Make sure you get the systm properly sized. If someone says you need larger than a 1.5TON A/C or more than a 40,000-50,000 BTU furnace I'd make them prove it with load calculations. Besides, your ductwork probably isn't large enouhg to handle more than 1.5 Tons (600 CFM).

[Driverfound]

If the current furnace has an HSI, it's likely a 80% unit. With such a small home, you may struggle to get a payback on a 95% unit...except that the tax credits cover the increased costs. So it might be a good time to get a matching system.

The 95% units are almost all Vairable speed are 2 stage, so you'll get added comfort in more mild weather.

Since your cooling season is realatively short, you might not get much payback on the A/C so I'd try and save some money there and just go with a basic 13 SEER unit (lowest now sold). You'll still save 30-40% on your cooling bills compared ot a 20 year old system that's probably around 8 SEER.


Make sure you get the systm properly sized. If someone says you need larger than a 1.5TON A/C or more than a 40,000-50,000 BTU furnace I'd make them prove it with load calculations. Besides, your ductwork probably isn't large enouhg to handle more than 1.5 Tons (600 CFM).

Thanks for all the info. I'm going to call some contractors in to give me a few quotes this spring and see where it goes. I realize how imperative a properly sized system is, especially in my case, as the supply ducts are run through a concrete slab and cannot be changed out easily, if at all. One of my biggest concerns aside from efficiency, cost and sizing is that the indoor unit is quiet. The furnace is right smack in the middle of the house, right off of the living room/dining room. The Rheem I have has no inducer fan for exhaust, and is almost silent, especially compared to the old Trane XE-78 I had in my old apartment.

[BaldLoonie]

Any 2 stage 95% that I know of will be grossly oversized for an 800 sq ft condo. In fact, small multifamily tends to be the most oversized application as dealers are scared to use very small units. Oversizing is not comfortable nor efficient! If you do replace anything, demand that an accurate heat gain/loss calc be done as a requisite to getting the job. If you replace the A/C, a new indoor coil is a must these days.

[Driverfound]

Comfort is important, as is efficiency and sizing. I'm going to be calling someone in to do a sizing calc and an estimate this week. I'll also ask if I would qualify for any tax credits with a more efficient unit. More than anything I want a system that is sized properly, and installed properly that will give me at least another 15 years without much trouble. Thanks again for all the help.

[motoguy128]

You may have trouble getting the tax credit on a properly sized unit. I think Carriers Performance series 80% and 90% furnaces are sized down ot 40,000 BTU and the Perfoamnce A/C's are available in 1.5 Tons.

Start with the right size then come bakc here and see if we can help finding some matches that meet the tax credit... if your installer hasn't found one.

[motoguy128]

Nevermind...lots of good matches on the smallest units. Here, found some good matches on the ARI website. Sometimes the smallest units have narrow cabinets that don;t match well. But this same model furnace also meets the tax credit with a 2 ton A/c or a 60,000 BTU furnace. So you should be ok either way.

16 SEER, 13 EER, 18,000 BTU capacity. Matched to a 40,000 BTU 90% furnace. ARI number 3323690.

http://www.ahridirectory.org/ahriDir...ultSearch.aspx


Carrier is just one brand. the other brands should be able to match this system.