furnace features

[John Dirks Jr]

I'm pretty sure I'm going to buy some hvac equipment and install it myself (except for the charging part). I'm pretty sure a 2 ton AC unit and a 70-75k BTU furnace will suffice.

I'll get a 95% efficient furnace but I'm not sure what features I really need. My choices rest between single stage vs two stage and variable vs non variable speed blowers.

My house is relatively small, manages air pretty good and we don't play with setbacks. We set for a constant 68 in heating mode and 74 in cooling mode.

Can I really benefit from added features of two stage burners and variable speed blowers or would my general situation do just fine with a less expensive single stage unit?

[Robert Jones]

Can I throw a small wrench into your planning by recommending a heat pump system instead of a separate furnace/ac unit. Overall efficiency might be worth it.

[Jim Katen]

I'm pretty sure I'm going to buy some hvac equipment and install it myself (except for the charging part). I'm pretty sure a 2 ton AC unit and a 70-75k BTU furnace will suffice.

I'll get a 95% efficient furnace but I'm not sure what features I really need. My choices rest between single stage vs two stage and variable vs non variable speed blowers.

My house is relatively small, manages air pretty good and we don't play with setbacks. We set for a constant 68 in heating mode and 74 in cooling mode.

Can I really benefit from added features of two stage burners and variable speed blowers or would my general situation do just fine with a less expensive single stage unit?

I'd encourage you to go for a variable speed blower. The nice thing about it is that you can set the blower to run 24/7 to keep the indoor temps more even and to constantly filter the air. With a single-speed blower, that strategy gets to be noisy and annoying. With a variable speed blower, it can run at a slow speed and you'll barely notice that its running. Depending on the equipment you get, it can also ramp up to speed slowly so that the furnace doesn't come on with a sudden rush.

The variable speed blower just makes the whole system quieter and less obtrusive.

For a house like that you don't need mutiple stages of heating or cooling.

I'd think that, in your area, you'd want to invest in the highest SEER AC unit that you can afford.

[Rick Bunzel]

I took the heat exchanger inspection course from Ellis Pratt several years ago and one of the students ask what furnaces he preferred for his own home. He basically said stay away from those condensing high efficiency furnaces. For the additional money you pay, there not worth it. He said the heat exchange will fail before you see a payback. His advice buy a plain old 80% efficient furnace and keep the filters clean.

http://www.heatexchangerexperts.com/

[kurt]

I'm not sure his advice is all that worthwhile now. The newer furnaces are pretty nice.

[AHI in AR]

I put furnaces with variable speed blowers in my previous home. They were really nice, coming up to speed slowly and quietly. Maybe it's just me but I appreciated the fact that they were a much more elegant solution than the typical forced air furnaces.

[Jim Katen]

I took the heat exchanger inspection course from Ellis Pratt several years ago and one of the students ask what furnaces he preferred for his own home. He basically said stay away from those condensing high efficiency furnaces. For the additional money you pay, there not worth it. He said the heat exchange will fail before you see a payback. His advice buy a plain old 80% efficient furnace and keep the filters clean.

http://www.heatexchangerexperts.com/

5 years ago I would have agreed. Not now.

[John Dirks Jr]

So these days are they using better materials in the exchanger, better methods of condensate management, or both?

[Jim Katen]

So these days are they using better materials in the exchanger, better methods of condensate management, or both?

Better quality control and better warranties.

A lifetime warranty on the heat exchanger invites the manufacturer to develop an interest in the longevity of the product.

[plummen]

I took the heat exchanger inspection course from Ellis Pratt several years ago and one of the students ask what furnaces he preferred for his own home. He basically said stay away from those condensing high efficiency furnaces. For the additional money you pay, there not worth it. He said the heat exchange will fail before you see a payback. His advice buy a plain old 80% efficient furnace and keep the filters clean.

http://www.heatexchangerexperts.com/

It depends a lot on the rest of the house on whether I reccomend an 80% or a 90plus.

If you have junk windows and no insulation in your attic I normally tell people to install an 80% and spend the extra money on insulation to keep some heat in the house.

On the other hand if you have a pretty tight house but you have an old brick chimmney that needs a liner with a really steep roof Id say go 90plus.

Another issue now a days is the fact 80% furnaces you buy are going to be left overs in the wharehouse since theyre being phased out .

[HVACMASTER]

The furnace must be sized to keep up at peak demand so of course you should get 2 stage (you dont blast the heat on highest setting in your car and turn it on and off constantly) you want a long run time for more even comfortable heat that wont dry out the air as much and is quieter and doesnt put as much stress on heat exchanger .....

True Variable speed will ensure correct air flow thru heat exchanger and coils for proper capacity and peak efficiencies. Variable can overcome poor duct design and thick filters. Most systems have inadequate air flow which variable can address when installed properly

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