2 stage versus modulating furnace
I am researching purchasing a new furnace and one service provider recommended a York modulating furnace (97% efficient) and another recommended a 2 stage variable speed furnace (96% efficient). The second service provider said that for my 1050 square foot bungalo (*which is all one level with an in-law suite in the basement) I won't see much difference between a two stage and a modulating furnace so I would waste my money if I purchased the modulating furnace. He recommended an Amana 2 stage furnace. I could also purchase a York 2 stage furnace. I need advice whether purchasing the modulating furnace will really make my living space (both floors of the house) that much more comfortable or if a 2 stage variable speed furnace will do the job just as well. Looking forward to learning more. Thanks for reading.
i would say 2 stage just more things to go wrong modulating gas valves. carrier has a 3 stage but its costly
Bear in mind that modulating furnaces are for comfort, not savings. If you are stepping up from an older furnace you will still see savings.
After living with one for 3 years, I wouldn't have anything else (inverter maybe). If you experience wide temperature swings and are cold right after the furnace shuts off, you'll love it. The key is proper sizing.
There are differences in the way different brands modulate. Do your homework.
Thanks for the advice. Just curious what type did you install and would you recommend it?
If you get a properly sized furnace, you'll be plenty comfortable with a 2 stage. It will still run almost twice as long than a single stage.
Plus with a vairable speed fan... which a good 2 stage unit would have, you can leave the low speed circulating fan running and it will help even out tempratures between rooms but use very little energy.
The main thing is to install the smallest furnace that a load calculation says you need. In your case it's probably a 40k or 60k BTU unit. But it depends on the building and where you live.
The quotes I've got so far recommend 60, 000 btu. Thanks for the response
Did they do a load calculation? I lived in a 1200 sqft single story ranch with a full basement, and it had no trouble maintianing 70F when it was -10F outside with a 60k BTU furnace. I probably could have used a 40k BTU. Actually it only went to high stage on setbacks and it cycled on/off high stage when it got below 0.
Originally Posted by dougielearner
Obvisouly location, insulation, house design and such all matters.
You must be in the arctic.
A 60,000 btu in a 1000 sq ft home, with decent insulation would most likely be oversized in most any climate. Trust me, I've seen way too many oversized systems. And seen many 40,000 btu units work very well in that size home.
Did they do a load calculation?
Don't let them talk you into a bigger unit by saying "it will run in first stage most of theme, so it's OK".
Also, I don't think you can get that mod unit in a 40,000.
Demand a load calc, and don't oversize. You won't be sorry.
"Hey Lama, hey, how about a little something, you know, for the effort." And he says, "there won't be any money, but when you die, on your deathbed, you will receive total consciousness." So I got that goin' for me, which is nice. - Carl Spackler
As far as both floors being more comfortable, that is a crap shot. Zoning would make that happen. You will likely end up with similar comfort on both floors. Ask about zoning if you want to improve comfort on a multi story home.
Slow down and don't get hosed. 60,000 that drops to 40 when your load range is 10-30,000 means you paid for 2 stages and got one.
Originally Posted by motoguy128
Get an energy audit & let us know the results, then the advice here will be really helpful.
Which makes more sense to you?
- turning your thermostat back and being uncomfortable. Maybe saving 5-10%
- leaving your thermostat where everyone is comfortable. Saving 30-70%
DO THE NUMBERS! Step on a HOMESCALE.
What is comfort? Well, it AIN'T just TEMPERATURE!
Energy Obese? An audit is the next step - go to BPI.org
, or RESNET
, and find an auditor near you.
I would suggest the modulating furnace. I think the smallest size they make is 60k. The ECM blower and ClimateTrak make it a really nice unit. I have been selling them for a few years now and have had very few repair calls. I have also gotten some great feedback about lowered gas usage.
A modulating furnace often lets you set the thermostat set temp a little higher. While still feeling just as comfortable. The longer run time of a mod makes a world of difference.
Yes I live in Northern Ontario and we often have temperatures -30 Celsius. I also own an older home and although I am updating insulation. The exterior is stucco so heat loss is an issue. Since I can 't currently afford to insulate and install siding and my current furnace is 15 years old I figured it was time to upgrade.
Originally Posted by 2old2rock