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misiek

join:2000-12-25
Round Lake, IL
reply to rockotman

Re: External air supply for an 80% AFUE furnace?

said by rockotman:

Why do you think that a furnace that is 15 years old will need to be replaced? With proper maintenance, that furnace should last at least another 15 years.

The inducer (I think that's what it's called) motor is getting loud. A service technician said it would cost a few hundred $$ to have it replaced. Plus the heat exchanger may go soon too, so that's additional few hundred. This furnace had trouble keeping up with really cold temperatures. The techs said it's a bit too small for our house.


mix

join:2002-03-19
Utica, MI

Every service tech says this about every furnace...

Inducer motors are easy to change yourself. See if you can find the part online to at least figure out the cost.



tschmidt
Premium,MVM
join:2000-11-12
Milford, NH
kudos:9
Reviews:
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reply to misiek

said by misiek:

This furnace had trouble keeping up with really cold temperatures.

Before you invest in a larger furnace may want to check out improved insulation if you have not already done so. That should pay big dividends.

If what mix See Profile said is true you can buy some time by replacing the motor yourself and seeing what effect better insulation has on energy demand.

/tom


Lurch77
Premium
join:2001-11-22
Oconto, WI
kudos:4

1 recommendation

reply to mix

said by mix:

Every service tech says this about every furnace...

Every single one of us are evil humans. Not a single one of us will ever look at your safety, comfort, or budget. We'll never warn you of possible issues unless we can get maximum money from it. Each and every one of us are just looking for your wallet, nothing more. Every one of us does this every day with every customer and every heating system. It's how we roll.


nunya
Premium,MVM
join:2000-12-23
O Fallon, MO
kudos:12
Reviews:
·Charter
·voip.ms
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They learned all their evil conniving tactics from electricians and plumbers.

I am curious about the subject though. Would an ERV make any difference in an old drafty house. E.G., would the "least path of resistance" rule apply to air as well?

In my house I have the furnace, water heater, bath vents, and dryer. I'm sure they are pumping copious amounts of air out of the house, which means air is coming in from somewhere anyway.
--
If someone refers to herself / himself as a "guru", they probably aren't.



ArgMeMatey

join:2001-08-09
Milwaukee, WI
kudos:2
Reviews:
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reply to misiek

said by misiek:

The inducer (I think that's what it's called) motor is getting loud. A service technician said it would cost a few hundred $$ to have it replaced. Plus the heat exchanger may go soon too, so that's additional few hundred. This furnace had trouble keeping up with really cold temperatures. The techs said it's a bit too small for our house.

I'm not saying service techs are dishonest. But whether he admits it to you or himself, he's got an interest in selling you a new furnace. He may just appreciate job security, like you and me, or he may be on commission. If you inform yourself and know what he's talking about, you'll feel better about your decisions regardless of his biases.

#1. Inducer, I agree with the others, it's typically not tough to replace yourself. However if you want to have it replaced preventively by a service tech, use that to your advantage by getting quotes from different dealers. They will want to sell you a seasonal package and free checkup but tell them you want a quote to just replace that one part and nothing else with the understanding that if they find more problems, you will have those fixed later. If you've ever had an auto shop tell you, "I shouldn't even let you drive that out of here," and left anyway, you should be well-prepared to deal with that eventuality. If there's a big problem they will have you talk to a supervisor or sign a statement that you've been informed of the problems and advised to fix them.

#2. Heat exchanger: Sure, it may go soon. Or it may not. Unless he has some verifiable figures on the actual life expectancy of your specific heat exchanger model, thank him for his observation and send him on his way.

#3. BTU capacity of furnace: Ask him for the Manual J calculations so you can see for yourself how far off the furnace output is, from what's optimal. Also try an online calculator to see what it thinks you need.

#4. Before jumping the gun on replacement, check out modulating furnaces. They cost more but if comfort is an issue, they can be a good solution.
--
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ArgMeMatey

join:2001-08-09
Milwaukee, WI
kudos:2
Reviews:
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reply to nunya

said by nunya:

Would an ERV make any difference in an old drafty house. E.G., would the "least path of resistance" rule apply to air as well?

In my house I have the furnace, water heater, bath vents, and dryer. I'm sure they are pumping copious amounts of air out of the house, which means air is coming in from somewhere anyway.

We have an old leaky house. I had an energy audit with a blower door test, and was given an ordinal list of improvements to reduce outside air infiltration. We did the top items on the list: Insulating all outside walls, weatherstripping doors better, sealing unused windows. Other items on the list were rebuilding windows to eliminate window weights, and then insulate those cavities, insulating basement walls. The ERV didn't even make the list. So in a loose house, your money is better spent on other stuff.

I also draw air with the bath and range vents, but I am not worried about backdrafting because I have a direct vent water heater and 90+ furnace drawing outside combustion air. Only the gas dryer draws combustion air from inside.

So anyway, after the insulation and weatherstripping, the auditor re-did the blower door test, showed me the reduced infiltration, and gave me my rebate certificate. With that, the state program paid for most of the audit and paid me for part of the improvement cost.
--
USNG:
16TDN2870
Find your USNG coordinates:
USNGWeb


Lurch77
Premium
join:2001-11-22
Oconto, WI
kudos:4
reply to nunya

said by nunya:

They learned all their evil conniving tactics from electricians and plumbers.

I am curious about the subject though. Would an ERV make any difference in an old drafty house. E.G., would the "least path of resistance" rule apply to air as well?

In my house I have the furnace, water heater, bath vents, and dryer. I'm sure they are pumping copious amounts of air out of the house, which means air is coming in from somewhere anyway.

An HRV/ERV takes in approximately the same amount of air as it exhausts. On the better units you can adjust the intake to exhaust ratio. But overall you are not bringing in a substantial amount of extra air for combustion. And the more you bring in compared to exhausting, you are lowering the ERVs efficiency anyway. It's bringing in more cold air compared to less warm air exhausting. So there is far less heat transfer to condition that incoming air.

For example, lets say your ERV brings in 100cfm. It is exchanging that air by also exhausting about 100cfm. This is what they do, create air changes per hour for better air quality. But your standard efficiency furnace is still consuming combustion air and pumping it out the stack. So where is that combustion air coming from? It's not from the ERV, as it is already pumping out what it brings in. Combustion air comes from same places it has always come from. Leaking windows, uninsulated walls, doors, vents, etc.


JustBurnt

@rr.com
reply to nunya

said by nunya:

They learned all their evil conniving tactics from electricians and plumbers.

Can't leave out Roofers