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Help figuring out criteria for replacement furnace!

Hi all,
We are looking to replace a gravity furnace in a 1937 Los Angeles home, with asbestos ductwork. The house is two-story and 1800 sq ft. We do not have A/C and are not planning to add an a/c. We would like to be more energy efficient if possible (and we hope to do attic sealing and add insulation), but we have a very limited budget, so we cannot go for those projects that require very high initial outlays. We also hope to get an energy audit before we do anything, but we would like to know how to understand/compare any initial quotes we are getting.
All that I know about heating is what I have been reading ******, and I just want to make sure I am getting the appropriate elements included within any quote from an HVAC contractor. I have some questions, so I just hoping that someone more knowledgeable than I can weigh in on the following.

* We currently have ducts with vents near the floor on the interior walls. Is the location of these vents appropriate for a forced air furnace?

*There is not currently a return register. Should there be one on each floor? How many?

* We have 8" ductwork. We will be replacing the ducts because we want to get rid of the asbestos, but is 8" the correct size for a furnace in a house this size?

*What is the rough estimate of the appropriate size of the furnace unit for this size house?

Please let me know if there is more information needed to figure out these questions & thank you in advance!

Re: Help figuring out criteria for replacement furnace!

Call 2 or 3 HVAC contractors for evaluation and estimates, then compare them. After you do that, we can discuss the details.

You may find out that you don't need to replace your ducts.

The furnace you have in your house now- is it the original unit? If it is, it;s pretty amazing that it was kept in the house since 1937.

Re: Help figuring out criteria for replacement furnace!

Thanks, I do believe it is the original furnace. It still works and a few people have said that it is in pretty good shape. The main reason for replacing it is the husband's desire to get rid of the asbestos-wrapped ducts. They are actually in pretty good shape themselves, but he is very very very risk-averse and wants them out sooner rather than later.

I've gotten one quote so far--which is why I started asking around on the forum, because some of the things he was saying seemed contrary to what I had read on the internet, but he came highly recommended. We will get some more quotes, but not sure when--perhaps next weekend.

The one HVAC person who visited was recommended by a friend as doing good work and he gave us a good price, but he said we only needed 1 return register (on the 1st floor), that the 8" ducts were the correct size, and that the location of the ducts (along the interior walls) was fine. That all seems contrary to what I had read, but if these things do not have a big effect on the comfort level or energy expenditure (particularly the location of the ducts--since that would likely be the most costly to change), then I would be happy to go with his very affordable quote (which included removal of the asbestos-wrapped ducts). He was also planning to install a York Guardian model# GG9S080B16MP11. I haven't found much on this model, but it is 95% efficiency and seems to be a budget model but lasts decently well (also costs under $1000). I am sure I could ask him to install a more expensive/ better version and just increase our quote if it seems like this is not a long-lasting model.

Re: Help figuring out criteria for replacement furnace!

If your husband is that risk averse to the asbestos wrapped ducts, then the last thing you should be doing is removing it. The most dangerous part of the asbestos is handling it. It was dangerous when first installed, mostly to the installers, but since 1937, any loose dust will have long since blown away, and it is dangerous to remove.

To remove this stuff safely as far as your family is concerned, the house will have to be completely incased internally with plastic so that all the dust from the removal will be trapped and removed with the plastic. This is time consuming and very expensive. If you are getting a cut rate removal job, I would be very cautious. The contractor may protect his workers with class A protection, but leave loose dust in your house.

There are methods of spraying the asbestos with an encapsulate that will protect you and your family and then just leave it in place. This will upgrade your protection, but just not disturbing it is a good choice.

Because of the mild weather in LA, it is hard to get any payback from high efficiency heating and cooling systems. It ain't like Vermont, 11 months of winter and one month of bad skiing.

Re: Help figuring out criteria for replacement furnace!

I would ask the a/c guy for a price on an 80% efficiency furnace, and leave the ducts alone, as mentioned above. Just have him check all the duct connections, and tape them.

Go with a Rheem furnace, I have had good luck with them.

I own homes that I rent out, they all have 80% furnaces, and they all do a very good job. There is no need for high efficiency furnaces in our area.

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