Capacity needed for 2500 sq ft house

[beenthere]

Ones as good as the other.

[Montreal_Canada]

I agree with beenthere. None of the furnaces you listed are variable-speed. I'd go with a variable-speed blower personally, for comfort and efficiency. Of course, properly-sized ductwork is necessary in any application to make a system work correctly (you mentioned that your old system worked well, though). For variable-speed furnaces, you'd be looking at Carrier's MVC, MVB or CVA (depending on efficiency) and Lennox's G60V, G61V or G71P (again depending on efficiency). A 2-stage variable-speed furnace wouldn't be a bad idea because as beenthere said there are some thermostats that can stage backup heat (I believe Honeywell's VisionPRO is one of them).

On Lennox site I see some fournaces to be with "Low-speed fan — Provides a consistent, continuous flow of warm air" - is it as good as variable speed ?

[RyanHughes]

On Lennox site I see some fournaces to be with "Low-speed fan — Provides a consistent, continuous flow of warm air" - is it as good as variable speed ?

When I saw this a little while ago I was confused myself. I couldn't find anything in their engineering documentation that mentioned a low fan speed setting. Does any Lennox dealer know if this furnace has a low fan speed setting for constant fan?

Update: I just looked closer into Lennox's engineering data for the G60, and it says "Terminal for continuous low speed blower operation." There's your answer. Looks like these things can be setup for continuous low speed operation. I'm not sure what the "low speed" is, though. This is good for comfort; however, a multi-speed blower cannot vary its speed and isn't as efficient as an ECM variable-speed blower.

[Montreal_Canada]

I agree with beenthere. None of the furnaces you listed are variable-speed. I'd go with a variable-speed blower personally, for comfort and efficiency. Of course, properly-sized ductwork is necessary in any application to make a system work correctly (you mentioned that your old system worked well, though). For variable-speed furnaces, you'd be looking at Carrier's MVC, MVB or CVA (depending on efficiency) and Lennox's G60V, G61V or G71P (again depending on efficiency). A 2-stage variable-speed furnace wouldn't be a bad idea because as beenthere said there are some thermostats that can stage backup heat (I believe Honeywell's VisionPRO is one of them).

When we talk for say MVB and CVA - there is a huge difference b/w 96 and 80 AFUE ... what is the price difference between them (as idea). And what about MVC ?. Thanks!!

[RyanHughes]

Sorry, it's against site rules to discuss specific pricing--even rough ideas. And I'm not familiar with Carrier's pricing anyway. You'll have to ask your Carrier dealer.

[Montreal_Canada]

Sorry, it's against site rules to discuss specific pricing--even rough ideas. And I'm not familiar with Carrier's pricing anyway. You'll have to ask your Carrier dealer.

Sure, I'm not asking about a price, but rather of ratio, I mean - both are variable and so ... but AFUE is too different, anyways, thanks !

[RyanHughes]

Montreal_Canada, let's get you on your own thread, since this thread belongs to the original poster, Nov3ice. You can continue post your concerns and continue your conversation there. Just go to the Residential HVAC forum and hit new thread up at the top-left.

Sorry for cutting into the original thread, Nov3ice; I lost track and forgot this was another thread due to the ongoing conversation!

[Montreal_Canada]

Update: I just looked closer into Lennox's engineering data for the G60, and it says "Terminal for continuous low speed blower operation." There's your answer. Looks like these things can be setup for continuous low speed operation. I'm not sure what the "low speed" is, though. This is good for comfort; however, a multi-speed blower cannot vary its speed and isn't as efficient as an ECM variable-speed blower.

So, that means the variable-speed blower will turn with anything b/w 0 and some speed constantly (or not) to produce a constant flow for filtering and temperature exchange, and the low-speed one will do samething, but with only one pre-adjusted speed only, right ?

[Montreal_Canada]

Montreal_Canada, let's get you on your own thread, since this thread belongs to the original poster, Nov3ice. You can continue post your concerns and continue your conversation there. Just go to the Residential HVAC forum and hit new thread up at the top-left.

Sorry for cutting into the original thread, Nov3ice; I lost track and forgot this was another thread due to the ongoing conversation!

Sure, sorry about that guys ! I will open new one, say Montrreal_Canada concerns ;-) Thanks !

[amd]

High efficiency equipment in a house that ins't well insulated is not a waste.
It would be nice for your heating and cooling bill if you could make improvements to youor homes weatherization.

With the proper thermostat, second stage will only come on when needed.
That may be 10° colder then when the furnace took over, or less or more. Depends on the house.

The additional money spent on a high efficiency system could go towards insulation upgrades and draft proofing.

I would take a well insulated house with an 80% furnace over a inefficient house with high end HVAC equipment any day.

[jrock52766]

with rising energy costs the question should not be "how much more will it be to upgrade now?" but rather "how much more will it cost me in utilities over the next 10 years if i go with the less efficient furnace?"