Our currently gas-fired furnace and AC unit are 20 years old and starting to have issues. Since the age doesn't really warrant putting any money into them, we are looking at getting them replaced. We've gotten two quotes to replace what we have (1 stage) systems which were about the same price ($11,000).

We had someone today who also suggested we could get a 2 stage system. Basically, the heat and the AC run at a lower level but for longer when appropriate, and then up to a higher level when needed. It doesn't seem that there are many differences in energy use, but it may be more comfortable to have it running more often but not blasting heat or AC. But... it's $5000 more.

Does anyone have an experience with a 1 stage vs 2 stage system? I'm getting the "up-sell" vibe.

By the way, we live in DC where we need to use both, and plan to be in the house another 7-10 years.

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Have you considered a heat pump? I have no idea if it makes sense for you personally but I'll probably look into it if/when I'm in the same spot.

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Quote
jardster
Our currently gas-fired furnace and AC unit are 20 years old and starting to have issues. Since the age doesn't really warrant putting any money into them, we are looking at getting them replaced. We've gotten two quotes to replace what we have (1 stage) systems which were about the same price ($11,000).

We had someone today who also suggested we could get a 2 stage system. Basically, the heat and the AC run at a lower level but for longer when appropriate, and then up to a higher level when needed. It doesn't seem that there are many differences in energy use, but it may be more comfortable to have it running more often but not blasting heat or AC. But... it's $5000 more.

Does anyone have an experience with a 1 stage vs 2 stage system? I'm getting the "up-sell" vibe.

By the way, we live in DC where we need to use both, and plan to be in the house another 7-10 years.

2-stage in terms of dual-compressor or just a variable speed fan (ECM) versus the older PCM fans that just switch on/off?

I'd get the latter (ECM variable speed blower fan) but a single-stage heat pump.

We have 2 systems... added a heat pump on a few years ago when we did an addition.

The system we are replacing is a traditional gas fired heat and AC unit (outside). I don't love the heat-pump so much. It gets really hot and humid in the summer and really cold in the winter, and I think heat pumps don't do as good as a job on those days.

The furnace is a variable speed 2 stage, and the AC is a 2 stage condensing unit.

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20 years ago already, so YMMV, we had a choice between single-stage, two-stage and continuously variable, with a corresponding increase in cost and efficiency. We settled on the two-stage for efficiency. The extra cost for continuously variable made me doubt the pay-off was worth the efficiency difference (something like 94% vs 96% efficiency, IIRC), plus the additional layer of complexity meant another point of failure. Our two-stage has needed no repairs.



Edited 1 time(s). Last edit at 01/18/2023 02:42PM by Acer.

Ultra low temp heat pump. Works down to -8ºF to -15ºF (USDA Zone 5). They come in 15 to 23 EER models. The seller I bought my house from was trying to abandon his promise to install a new furnace. I would have forgiven it if these Ultra Low temp models were as widely available as they are now.

The big problem is finding a contractor who will guarantee the installation and performance ($$$). It's actually pretty easy if you have automotive piping or plumbing A/C experience, but the EPA usually requires a licensed refrigerant tech to sign off. Multi-zone splits save a few percent in energy costs by not heating up forced air ducting.

Choosing the Best Cold Climate Heat Pump https: //carbonswitch.com/best-cold-climate-heat-pump/

https: //www.fujitsugeneral.com/us/residential/technology/xlth-low-temp-heating.html

HomeDepot sells "Pioneer" branded low temp splits.

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In tha 360. MRF User Map

I’m just a little south of ‘Very Cold’ and I appreciate staying warm when it is -20, -30 and, rarely nowadays, even colder. We have a well but pumping water negates any savings. Ground-source is too expensive to install, especially below the frost line.

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Saint Cloud, Minnesota, where the weather is wonderful even when it isn't.