Gas Furnace Replacement -- Advice Requested

[Joseph'bidness]

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[Joseph'bidness]

I am learning the forums, seems like to many rules

[Dad]

I am learning the forums, seems like to many rules

Just in the AOP area and for a good reason.

May want to avoid the AOP until you get your verifications to answer and hang out in the other forums for now.

[motoguy128]

Your heating and cooling requirements are so minimal, I don't think you'll get much out of fancy equipment and controls. Just get a 2 stage furnace and single stage AC properly sized. Just a basic 2 stage thermostat will work fine. I like the Honeywell Focuspro for a basic thermostat since it has adjustable cycle rates. Unless you get a good utility or mfg rebate, I'd just put in a basic a 13 SEER unit as little as you'll use it. With a vairable speed blower on the 2 stage furnace, it will provide 14SEER anyway. Proper sizing or even undersizing it slightly if you're borderline will make a huge difference on efficiency.

Modulating is nice, but a 45k BTU 2 stage will go jsut as low if you have a small load. The smallest modulating furnace is 60k BTU.

IF you have a smaller house and a load under 40k BTU's I would encorage looing at a combi boiler and using a hydronic coil for heating. Then you have just a single appliance for hot water and heating and the water temp can be varied based on outdoor tmeprature, so the capacity of the system can vary all the way down to nearly 5% capacity.

[tigerdunes]

To add to the previous post.

If you elect a two stage furnace, you want a true two stage thermostat that controls staging not relying on a timer that will leave you in high stage all the time whether needed or not.

IMO

[breaks911]

I received the 3rd bid yesterday. This company did perform the manual J and came up with a requirement of 71,000 BTU and recommended a 110,000 BTU two stage. They felt with a little larger unit Does that seem reasonable based on the requirements from the manual J?

I feel like I'm almost there...

Thank you!
Ryan

[beshvac]

What's the cooling load?

[breaks911]

Great question - she didn't leave me with that data point. I haven't been interested in replacing the AC, so perhaps that is why she didn't provide it to me...

[beshvac]

Great question - she didn't leave me with that data point. I haven't been interested in replacing the AC, so perhaps that is why she didn't provide it to me...

It's relevant because the furnace needs the capability of covering the cooling cfm. With a heating load of 71000 a 90k furnace will do the heating load, as long as the furnace has a big enough blower to do the cooling load.