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AC shot, change furnace too?


leflemin
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My HVAC guy told me that both the AC and furnace are oversized for my rental property. He recommends replacing both (furnace is 15yrs old and oversized, AC was mutilated by copper-seeking drug addicts). The furnace is working fine. He said if I replace the AC and not the furnace, the coil will be too large to fit in the new furnace when it comes time to get it. Apparently he can't put the new AC sized for the smaller furnace in the larger furnace to allow the furnace to be switched out later.

Is this really true? Seems like a smaller coil would fit in the larger furnace, but then again I don't know. I'd rather not have to spend the $$ for the new furnace now when the old one is working fine.

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For closet installed gas furnaces in my part of Louisiana, the evaporator coil sits in a coil cabinet that is installed on top of the furnace. If your coil fits inside the furnace then your guy likely has a valid point in wanting the furnace changed, though I've never seen such an appliance. If it's on top, it's probably not necessary but perhaps gives you more value for your dollars if you change it, especially if the furnace already has 15 years of mileage on it. More labor and custom ducting would be needed to match up the new coil cabinet to the existing furnace. I've done jobs like this that took all day long to complete. With a new furnace, a perfect match is obtained right out of the box.

If it's a horizontal installation, there's no need to change the furnace.

Marc

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I haven't gotten any other quotes, though perhaps I should. I've used him before on some other projects, and have just gotten lazy on bidding things out. I'll try to provide more info on the furnace by tomorrow (brand, size, maybe a picture), after I get over to the house.

There are many things that go into to sizing a furnace & A/C unit. If you read through posts here you should be able to dig up some rule of thumb ideas but no one can address your situation from a computer. Time to put your dialing finger into action.

With regards to the 15 year old furnace. How long are you going to keep the property, who pays for utilities etc. Again, something that none of us can advise you on.

Good luck.

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in my opinion spend it now to replace both then you have a good warranty and a more efficient product and it will cost you less now then later, what happens in a week or so when the heat exchanger cracks or the board controling it shorts out or the gas valve malfunctions jsut my opinion tho.lil more now or alot more later plus having to inconvienence the tenant by fixing it twice all thing that should be considered and make sure the work is done by a licensed professional that will show you a load calculation he/she has performed on the property to correctly size the unit and ask if it will be installed by certified techs such as NATE or ACCA Excellence like any investment you only reep what you sow

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If you have new windows and are no longer using incandescent lamps, and now have your exterior house/envelope sealed and insulated better than when the prior furnace was installed, then *proper* downsizing will yield energy savings. Please keep in mind that *proper* sizing is not usually done.

You should also keep in mind that you are not only getting a new furnace if that is installed. You are also getting a new control system also. This means that if there a problem, the contractor is responsible for all of it and not just the coil. If there is freezing or another problem, he has to fix it - he cannot blame your old furnace nor your old control system.

If you don't have the money, then that is different case. My wife, for example, can preach to me all day that our friends new house that is 4 times as large uses about 2/3 the energy as ours - but she isn't getting a new house even if was a good idea!

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Any time my clients replace an AC system, I always tell them that they're pretty much crazy if they don't spend the few extra bucks to have a Heat Pump. It's essentially all the same components with a few more thrown in. Don't miss such a super opportunity. You can do that and your furnace will go into retirement as back up heat - barely ever working.

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Any time my clients replace an AC system, I always tell them that they're pretty much crazy if they don't spend the few extra bucks to have a Heat Pump. It's essentially all the same components with a few more thrown in. Don't miss such a super opportunity. You can do that and your furnace will go into retirement as back up heat - barely ever working.

A lot depends on location Mike. I'm not sure that would hold true for Frostbite Falls, MN.

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Any time my clients replace an AC system, I always tell them that they're pretty much crazy if they don't spend the few extra bucks to have a Heat Pump. It's essentially all the same components with a few more thrown in. Don't miss such a super opportunity. You can do that and your furnace will go into retirement as back up heat - barely ever working.

A lot depends on location Mike. I'm not sure that would hold true for Frostbite Falls, MN.

True, but a few years ago here I state they'd be in Canada soon. Folks said I was nuts. Now they're in Canada. They've come so far.

Wouldn't it be worth having one, even if it only provided heat 25% of the time, as cheap an add as it is? Just wondering...

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I serviced ACs and heat pumps for many years. I'm in south Louisiana and when my system needed replacement, I selected an AC. The added installation cost and servicing needed for a heat pump just wasn't worth it.

A few decades ago, people in my area began installing recovery units on their HVAC systems to heat hot water from discarded condenser heat. It turned out to be a short term fad. Too much trouble to service it. Servicing costs tend to skyrocket with increasing complexity.

It's justified in some climates, not in others.

Marc

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Heat Pumps have always proved to be an interesting subject. Home owners in general have out-dated opinions about them (Not that you guys do).

I know that when I changed out my 1984 heat pump for a new one in 2005, it cut my electric bill literally in half. That's how far they had come in eleven years. And the register temps are within a few degrees of furnaces.

It would be interesting for someone to actually crunch some serious hard numbers about them in comparison to furnaces. I'd love to see the results, come what may.

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