Is a high-efficiency furnace worth it?

Factual Questions
1

My wife and I have purchased a new house and we completed our house inspection this past weekend. We knew going into it that the furnace and the air conditioner would likely need to be replace in the near future - and we were correct.

When I mentionned to the house inspector that I was thinking of putting in a high-efficiency furnance, he was most against it. He told me that I would never recoup the spread in cost between a high-efficiency furnace and a conventional one. Among the reasons he gave were:
[ul]1. High-efficiency furnances do not last as long as conventional ones - the lack of a pilot light allow condensation to form within the unit contributing to early failure

  1. The savings every year in gas are not enough to cover the ~ $1500 spread in the cost of the furnaces

  2. Repairs on parts will be higher[/ul]
    Even mid-efficiency furnaces are not preferable to convential furnaces. So, ignoring the societal obligation/costs of using a less-efficient furnace on the worlds’ natual gas supply, are regular, cheaper furnaces less costly to own and operate?

2

Most of this sounds like BS to me, but I don’t have any facts to back up the opinion, so I’ll leave it to others. However, this part:

I believe I can address. First, I didn’t know anyone still made furnaces with a standing pilot light. They waste gas, they have to be manually relit following any interruption in service, etc., etc.

Beyond that, a bit of first-hand experience. My furnace has an electronic ignition. It was installed in 1986, meaning that it’s coming up on its 18th birthday. Last year, I had the furnace checked/cleaned, and the service guy said that it was very clean, with no traces of rust at all. So unless you’re living in a swamp…

3

Another thing to consider is this;
FWIW-
High efficiency furnaces take longer to heat the house. You have to start them earlier and run them longer to get the same effect. Or you may just be forced to leave them on depending on the occupancy of the house. My old furnace would heat the house while I took a shower in the morning. The new efficiency one takes about 5 times as long to do the same thing.
FWIW-

My thoughts. High efficiency, but- Keep the setting at the same temp except for the mid-afternoon hours, when it can be turned off. This should allow even heating of the house without the furnace having to work much.

4

That’ll depend a lot on where you are, and what the climate’s like. ON is Ontario, right? What kind of temperatures do you get in Mississauga? For how much of the year is your furnace typically running? Or, I suppose to get right to the point, how much do your gas bills come to, over the course of a full year? I can guarantee you that an efficient furnace wouldn’t be worth it in Alabama or most of Texas, but it might be in the Frozen North.

5

My old 50% NG furnance died about a year ago.

My furnance guy said in the old days the theory was to put in a big unit but now to put the smallest possible–furnances are most efficient if they run a lot.

If you run the furnance a 100 days a year and the cost difference is only $1,500, I think you should consider the high-efficiency one.
NG prices have gone up a lot in the last year or so and who knows where it will end.

In any case, you need to talk to furnance people, they are likely to know more about it than home inspectors.

6

whuckfistle’s experience has nothing to do with the efficiency of the furnace. It’s a size issue, not type.

When we bought our furnace, there were basically two choices: high efficiency and really high efficiency. Pilot lights? Got to be kidding me. Went high efficiency and never looked back.

mske, you got a really lousy inspector on your hands. That’s not good. Sorry.

7

ftg - correct. Here is a cite to back it up. This is a very good link for anyone considering a furnace or if you just want to know ALL about everything associated with them.

Link

“The properly sized one also has a better chance of heating the house evenly. Today, bigger is not better.”

8

I got a new NG furnace about 2-3 yrs ago. The guy recommended against a high eff. due to:

1 - the chimny would eventually rot out due to condensation (high eff. furnaces need a different material)

2 - repairs are more often and more expensive, the electroics involved are somewhat extensive to keep everything ‘just right’.

I think there was a 3 also, but forgot.

Anyhoo, I don’t think pilot lights are used anymore.

9

As a mechanical engineer who (years ago) installed furnaces, I recognize an installer who is paranoid about new technology. The electronic controls apply to all furnaces today, regardless of type. Pilot lights are a thing of the past. In cold climates, high efficiency is the only logical choice, especially with the continuing rise in gas prices.

The calculations are simple. Take your annual gas bill and estimate how much of that is due to heating (most of it will be). Using your current efficiency of the furnace, calculate how much gas is actually heating the house. For example, if your annual bill is $1000, and you have a 70% furnace, you are getting $700 worth of heating. With a 95% furnace, you will get that for $736 saving you $264 per year. If you only had a 50% furnace now, you would save $474 per year.

With high efficiency furnaces, the exhaust is wet. You don’t use the chimney because it’s not warm enough to generate a draft. You install plastic intake and exhaust pipes through the side of the house.

Furnaces should be sized just large enough to heat the house by running constantly on the coldest day. (Interestingly enough, this is less critical with high efficiency furnaces than convential furnaces because they don’t lose heat through the flue when not operating like conventional furnaces.)

I have a high efficiency furnace. It’s 10 years old. It performs flawlessly and has never required repair or adjustment.