Which is the best choice

[LivingAlmostLarge]

Okay here is our options. We are looking to install a new a/c into our house. Our current furnace is 20+ years old. Our neighbor just remodeled and had to upgrade their system because it is too small for the doubling of the sq footage of their house. So they have a 10 year old furnace and a 5 year old ac they are giving to us for free. So we got a quote from their guy and it is $3k to install the furnance and a/c. It is $6k to get a new furnace and install the used a/c. It is $15k to install new both.

If we do this we get stuff a lot earlier. I get another quote next week but then I have to wait until october for my 3rd quote. Also installs and orders for new items are running 12 weeks out. Yeah life is hard and busy for these HVAC people.

I am leaning to the $3k solution. My DH feels like if the furnace breaks we need to pay $6k to put it in so he's leaning to the $6k. Which makes the most sense and why? Ask any questions.

[LivingAlmostLarge]

suggestions?

[ua_guy]

Are both the furnace and AC the right size for your house? That would be the first question. If they are improperly sized, I wouldn't put the used stuff in.

Are the installers going to pull permits? If not, I wouldn't use them.

If at least the furnace is right sized, that doesn't sound horrible to have the used one installed, but I'd immediately plan on having some go through it and do a thorough inspection. Heating season is upon us. About 20 years is all I'd expect out of a furnace before stuff starts going out, so there could be some good life left in the used unit, if it's been taken care of.

Installing the AC is the kisser because it requires running refrigerant lines all the way to the furnace and putting an evaporator type unit in the stack, I don't remember if they're called that or not. So if your AC is across the house from the furnace, they have to run lines, more lines for condensation, power to the AC unit, and maybe upgrade your thermostat too. Plus clearing and installing a pad/base for the AC unit outside. Whatever they install, if you go with used, make sure it will support a new unit too.

[Fishindude77]

Spend the $$ and put in new stuff if you intend to live at that location for any length of time.
You could easily wind up with more expense by installing used equipment, as it will fail much sooner and you'll be doing another replacement.

[LivingAlmostLarge]

It's the right size and yes permits and the a/c is new to us but they are installing everything and we were planning on staying less than 5 years. Preferably as soon as possibly and into something larger. We've been here 4.5 years but we would love something newer and bigger and would have moved last summer if not for changing jobs.

[bjl584]

Since you are planning to move I'd go with the used option and save the money upfront. A 5 and 10 year old unit has lots of life left in it.

[LivingAlmostLarge]

Since you are planning to move I'd go with the used option and save the money upfront. A 5 and 10 year old unit has lots of life left in it.

Update the newer furnace will be High efficiency but the used 10 year old unit is 80%. Would it be worth replacing that but using the old AC?

[bjl584]

Update the newer furnace will be High efficiency but the used 10 year old unit is 80%. Would it be worth replacing that but using the old AC?

that might be a good plan.
you could probably get your current AC serviced and charged with new coolant and it will be fine

[LivingAlmostLarge]

What are the chances the ac craps out or furnace? Quote the costco guy is $13k plus 15% rebate but includes permits and electrical. But 80% furnace not 96%. Our furnace is 2002 so 19 years old and it's a 12-15 year rated. The guys who installed it came out and gave me a quote.

[bjl584]

What are the chances the ac craps out or furnace? Quote the costco guy is $13k plus 15% rebate but includes permits and electrical. But 80% furnace not 96%. Our furnace is 2002 so 19 years old and it's a 12-15 year rated. The guys who installed it came out and gave me a quote.

hard to really say.
my furnace is 30 years old and works fine. I'm sure that it is inefficient but it still functions just fine.
I keep it cleaned and serviced and have only had minor problems over the years.

[myrdale]

What are the chances the ac craps out or furnace? Quote the costco guy is $13k plus 15% rebate but includes permits and electrical. But 80% furnace not 96%. Our furnace is 2002 so 19 years old and it's a 12-15 year rated. The guys who installed it came out and gave me a quote.

My house was constructed in 1996. The AC / furnace is still original.

In 2006 when I purchased the house, the inspector told me the AC was undersized and the furnace was horribly inefficient.

Fifteen years later they still work like a charm.

I've never had it serviced. Each year when I have the gas turned on, I hold my breath for a moment waiting for the gas company tech to say everything looks great. Each summer it takes a bit to cool down, but insulation in the attic, new windows, and I believe the house wrap & new siding have helped greatly.

If you're not having problems, personally I would recommend not doing anything.

[LivingAlmostLarge]

My house was constructed in 1996. The AC / furnace is still original.

In 2006 when I purchased the house, the inspector told me the AC was undersized and the furnace was horribly inefficient.

Fifteen years later they still work like a charm.

I've never had it serviced. Each year when I have the gas turned on, I hold my breath for a moment waiting for the gas company tech to say everything looks great. Each summer it takes a bit to cool down, but insulation in the attic, new windows, and I believe the house wrap & new siding have helped greatly.

If you're not having problems, personally I would recommend not doing anything.

I want AC though and it makes sense to do something about our old furnace. Myrdale does it make sense to replace it with something more effiecient and if it doesn't work then you aren't rushing at the last minute without anything?

[Fishindude77]

I believe the old HVAC equipment was 80% efficiency whereas the new stuff is something to the tune of 96%.
They make them more efficient with variable speed fans, better controls, less electrical use, etc. I don't think you'll see enough $$ savings in your utilities to warrant an upgrade if your only goal is to get more efficient equipment.

If you don't have AC and want AC in your central HVAC system, then by all means add it. As stated earlier, I would not waste the time or money pairing new AC with an old furnace. May as well change the furnace out too and upgrade to all new, high efficiency stuff.

You could also easily install a window AC unit, or permanently install one in a wall opening if you want to go the inexpensive route.

[myrdale]

I want AC though and it makes sense to do something about our old furnace. Myrdale does it make sense to replace it with something more effiecient and if it doesn't work then you aren't rushing at the last minute without anything?

I miss understood. So you do not have AC at all currently? That changes my answer.

I am assuming the AC you are receiving is the coil which would be mounted in line with the furnace and the fan/compressor/condenser coil (all that stuff in the box that sits outside the house). I am also assuming the furnace has a blower attached and you already have supply and return duct work in place. If all that is the case, I think you will be OK to install the used AC with your existing furnace. Your HVAC tech will have to confirm the blower with the furnace is sufficient for blowing air though the coil with out it freezing over and that the coil is not too much of a restriction on the blower that it dramatically reduces your air flow though the house.

Does it make sense to upgrade for efficency?

My gas bill runs about $100 per month, of which about $30 is taxes and surcharges. So I use $70 in gas per month at an assumed 80% efficiency. $70 x 0.8 = $56 is what I would use if I was 100% efficient. $56 / 0.95 = $58 if I was 95% efficient. I would save $70 - $58 = $12 per month with a new more efficient unit. I only run gas for 5 months a year, so I'd save $60 per year. If a new furnace is $6,000 then $6,000 / $60 per year = 100 years. I'll be in the black by the time I am 139 years old!!

People make this argument about cars all the time for saving gas. It is rarely a true justification when you do the math.

[LivingAlmostLarge]

No we do not have a/c at all. We do have the duct worth. The furnace is pretty old and most are only rate for 10-12 years and it's 10 years. I think we need a new furnace. It's pretty expensive to $7100 for used AC and new furnace. But new is $13k. I'm getting one more new estimate.