Author Topic: Replacing Furnace and AC  (Read 3785 times)

2527

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Replacing Furnace and AC
« on: March 23, 2014, 12:41:34 PM »
Both my forced-air gas furnace and AC are 16 years old, and the furnace has required repair twice in the last three months.  (The technician says one time may have been caused by an insect damaging the ignitor, which isn't really an age-related problem.)

Because we live in a town house, I think a geothermal heat pump isn't possible.

I'm thinking of replacing them in the next year or two.  Any advice?

Things to look for in models?
Would having one company do both at the same time save money?
What to look for in the company I choose to do the work?
« Last Edit: March 23, 2014, 12:52:07 PM by 2527 »

Emilyngh

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Re: Replacing Furnace and AC
« Reply #1 on: March 23, 2014, 01:30:39 PM »
We just had a similar situation and went with an all electric heat pump setup to replace both our oil furnace and AC.    Looking into all of the options electric is less expensive than oil (and will probably stay that way for a while).    We LOVE the heat pump and are saving more than $1k a year with it vs what we were spending on heating/cooling before.   

The whole thing (including the backup electric coils for super cold days and the heat pump with removal of the old stuff and installation of the new) was $5k-something.   But, we got quotes for other companies for the same work of in the $7ks, so super glad we got multiple quotes.

My understanding is that the cost of natural gas is less than going all electric, so you probably would want to get a new gas furnace vs the electric backup coils we got.   However, I would look into using a heat pump with the new gas furnace.   The heat pump will help a ton with the furnace's efficiency, as well as act as your ac (so you'd basically get it to use as your ac, but it could also be used with the furnace to improve efficiency).   

I would recommend contacting several companies, getting quotes from each for (a) new gas furnace and ac, (b) new gas furnace and heat pump, and compare it all, taking into account projected savings for increased efficiency of heat pump.   I would guess that getting one company to do it all will work the best, but get quotes from several.
« Last Edit: March 23, 2014, 01:32:23 PM by Emilyngh »

2527

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Re: Replacing Furnace and AC
« Reply #2 on: March 23, 2014, 02:33:48 PM »
Emilyngh,

You provided interesting ideas.  I suppose it would be possible to use a heat pump for cooling and for heating when the outside temp is around 50 or higher. 

Can I ask where you live?  We live in Philadelphia, and it routinely goes down to around 10-25 deg F, so we do need some kind of furnace.

Thanks!

Another Reader

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Re: Replacing Furnace and AC
« Reply #3 on: March 23, 2014, 03:15:03 PM »
There's a thread on this subject here started by tooqk4u about 15 months ago.  He lives in New Jersey, so the climate is similar to yours.

The furnace should go at least 20 years, unless it's a really cheap brand.  My furnace was 23 1/2 when the circuit board went out.  I'm in California, so the A/C unit is still going at 23.

My conclusion was the high efficiency units were wasted money in a mild climate.  The 80 plus percenters penciled out cheaper overall for me.  High efficiency furnaces need different venting as the gases condense and will rust out sheet metal.  There's an added expense to replacing a conventional unit with one of these.  You also should consider multi stage furnaces.

Trane generally has good reviews and I'm happy with mine.  The 23 year old A/C is also Trane.


2527

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Re: Replacing Furnace and AC
« Reply #4 on: March 23, 2014, 03:28:39 PM »
Thanks.  They were chosen by the builder when the house was built, so probably not the best.  I think the technician I was talking to mentioned multi-stage units.

DoubleDown

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Re: Replacing Furnace and AC
« Reply #5 on: March 23, 2014, 03:58:32 PM »
Whenever you finally decide to replace your HVAC, the Spring months (now until about late April) when the weather is mild is the perfect time to do it. You should be able to negotiate a 30-40% discount off the usual price since the HVAC dealers are less busy and hungry for business.

Emilyngh

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Re: Replacing Furnace and AC
« Reply #6 on: March 23, 2014, 07:47:59 PM »
Emilyngh,

You provided interesting ideas.  I suppose it would be possible to use a heat pump for cooling and for heating when the outside temp is around 50 or higher. 

Can I ask where you live?  We live in Philadelphia, and it routinely goes down to around 10-25 deg F, so we do need some kind of furnace.

Thanks!

Sure, I live in Virginia.   It doesn't usually routinely get down to 10-25 here, but we just had a cold winter where it was down there fairly often and things stayed toasty.

Almost regardless of where one lives, you would need a furnace in addition to the heat pump.   The idea is that the furnace then only kicks on when the heatpump can't handle things  (they have special thermostats to control this, ours was installed when the company installed the heatpump system and its cost included).   We have a furnace too, it's just electric (the electric coils I was referring to), and only kicks on when it gets down below 20-30 (the heatpump definitely heats well by itself considerably below 50).  The heat pump still runs when the furnace kicks on, increasing its efficiency.

Basically, if you went this route, you'd get a new gas furnace plus a heat pump (heat pump in place of the AC, but would also be used with furnace as I described).   It would cost more than just furnace+ regular ac, but it should be more efficient for both heating and cooling.   You'd have to get quotes for both options and run numbers regarding if it's the better deal overall.   For us, it definitely was (like I said whole thing cost $5k-something and has been saving use more than $1k a year), but we also had oil before, which is more expensive than natural gas, so it may or may not be worth it for you.   Just something to look into.
« Last Edit: March 23, 2014, 07:57:56 PM by Emilyngh »

Thegoblinchief

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Re: Replacing Furnace and AC
« Reply #7 on: March 24, 2014, 06:19:30 PM »
For rating actual contractors, there is Angie's List and general google-fu. Not sue if HVAC falls under remodeling, but if it does, see if they're a member of the local NARI chapter.

Personally, I would research the efficiency level of your current units. Assuming the furnace is high-efficiency, there's not a whole lot to be gained in operating costs by replacing it. I plan on running my  systems into the ground, as the furnace is now a Theseus' ship of components now mostly less than 5 years old. We even lucked out and had a major part fail (secondary heat exchanger), only to have it still be covered by a 100 % warranty despite being 17 years old.

By all means get a quote or two, but I'd just throw that into a savings bucket until you actually need it. And maybe you'll never actually need to replace them while in that current house.

We have Carrier units for both heating and air.