Is it worth upgrading to High Efficiency furnace?

[kevins_news]

My house (and furnace) is now 1.5 years old. Brand new construction

1.5 years ago. Since it is our first house we didn't think about things like putting in a different furnace. We picked the colors, cabinets, hardwood, countertops, and just let the builder put in all their default models for things like doors, windows, furnace, etc.

I assume i have what people call a Natural Gas Mid Efficiency furnace. Since all the high efficiency ones advertize multiple fan speeds (which mine doesn't have) i would assume mine isn't one of those.

First some questions:

Are the energy savings from HE furnaces in the electircy needed to run the fan? Or the efficiency of burning the gas (ie uses less gas to make same amount of heat)? Or something else? And what is the purpose of multiple fan speeds? Is this so you can leave the fan on a low setting constantly to keep air circulation happening? Other than allowing the air filter to be constantly working, what is the purpose of this?

Would it be worthwhile to replace mine with high efficiency even though it (and the building) is so new. two story, 1700 square feet townhouse. On the main floor only two walls are exposed to the outside. The other two walls are shared with neighbouring townhouses. Our entire 2nd story is exposed though since neither neighbour has a

2nd floor.

We are pretty energy conscious so i bet the furnace is already running less than the average household. I'd hate to spend $3000 (Canadian) on a furnace and find out i save only $100 a year in gas/electiricty.

Are there any theoretical numbers? A TV commercial says "It will save the average household X dollars a month" but with no indication of what "average" is. Maybe someone has a study where a mid efficiency furnace runs for X hours a day to heat the house, and a HE furnace would only run for Y hours. I could use that ratio to estimate something.

Any thoughs appreciated.

[Jerry G.]

First of all, don't listen to TV adds directly. To know what you may save will be a complex issue. There are many factors such as the actual required BTU's, how the heat will be distributed, the type of air flow effect, the heat loss in the home, and other things I can not even think of at this time.

There is also the ratio of the cost of the amount of energy difference between the two systems to give you the BTU's you require in the first place, and the system efficiency. When you sit down and scientifically work in all the factors, since your home is not a thermo precision environment, you may find that the results can be different than what you speculated in the first place.

It would take someone with a lot of experience and knowledge to really work this out for you. If you call in one of those salesmen from these companies, all he will see is his commission for selling you a system. He will then come up with all kinds of charts, figures, and examples to justify what he is going to sell you.

For an example, you can look at what your neighbours are doing since the climate of the area is the same, and their house construction must be similar. You can enquire to them about their heating costs, and type of heating system that they have. You have to factor in, if they are leaving the doors, or windows opened more often, and or leaving the garage opened longer. These things will show a difference on the average. There is even the factor of how the wind blows on the building, how much sun light they are receiving, and even the colour of the outside walls and roof in some cases. Darker colours will tend to heat up more when the sun is shining. This will contribute to a slight amount of less heat loss, even though the house is insulated. In the summer, a dark coloured exterior may infact increase the air conditioning costs.

If you look at the cost difference that you may save, over the lifespan of the heating system you choose to change to, and the maintenance required, you may find that there may be very little recovery or non at all, that makes it worth the time and effort.

If you do not have central air conditioning, you may want to consider a heat pump. this would cost about the same or a bit more than changing a furnace. With temperatures that are not colder than about -15 Cells (depending on the type), the heat pump will act as a heater, and will air condition in the summer. These are more efficient than most other systems. If you have a central system that uses forced air, there will be no need for extra duct work. You may recover some of the cost, but there are other conveniences with this type of system.

[Art Begun]

Even if you saved 30% (highly optomistic) it would probably never pay for itself. Besides, in 10 years when your current furnace may need to be replaced, there will be even more efficient furnaces on the market at lower prices.

furnace.

purpose

townhouses.

[HeatMan]

In line...

It probably a multi speed blower, even if it is a builder's grade furnace. US Energy code says the lowest efficiency furncae out there is 78%. I haven't seen a 78 in a few years as most are 80%.

Some is in the blower efficiency, but not all. Mostly it has to do with the efficiency of the burning gas.

Furnaces are set up for a specific temprature rise. The multiple speeds are for setting this 'Delta T.' Some of the equiptment has a setting for continous circulation for better air filtration, but probably not yours.

If you asked me this question while I was at your house, I'd stifle a grin and say a resounding "NO!" You'll never make the return on your investment, in my opinion.

Good for you.

Don't beleive everything you hear. I'd like to think those commercials are for the people that have furnaces a lot older than yours.

You're welcome.

[R Doornbosch]

OK but what about the difference between a new oil furnace and a new natural gas furnace? I was all set to go with a new high efficiency natural gas furnace when I started talking to the local heating guys who mentioned that the delivery cost of natural gas keeps rising and that they think a new oil furnace would cost less in the long run. Any ideas or comments?

[Michael Daly]

Years ago they told everyone to switch to gas, since oil costs keep rising. It's a cyclical thing - we used to heat with coal, coal oil, oil, now gas. Every one has its day and advances in technology, changes in relative cost etc will keep us changing heating methods every so often. If fusion technology actually happens (1st fusion plant is scheduled to be build "soon") we may end up switching to electric ground-source heat pumps.

What you want to do is go with the most efficient "system", not furnace. A high efficiency furnace in a leaky, uninsulated house is not as good as a low-efficiency heater in a well-insulated house. Some passive solar houses use wood heat for a backup and wood heat is not very efficient - it nonetheless creates a cost-effective solution.

If you have an _old_ inefficient furnace, replace it. Otherwise, fix up the house so that the entire _system_ is efficient.

Mike

[kevins_news]

Thanks to everyone for the responses. I have friends who have bought old houses and need to replace their 20-25year old furnaces. They're buying high efficiency ones. While it is a good idea for them, i kind of figured it wouldn't be for me.

Done. We like it cold at night. Especially since the wife is a heater herself.

Done.

Yep.

Bingo. How do i do this? I noticed when i messing with a phone outlet on one wall. It's a wall that is perpendicular to an outside wall (one of the walls my townhouse shares with the neighbour). The outlet is 8 feet in from the outside wall. When i took off the coverplate i could feel a slight cold air breeze. Is this somehow pluggable right around the outlet or do i have to track down the hole in the vapor barrier on the outside wall?

Just FYI, this 'party wall' between townhouses is made of my paint, drywall, studs&insulation, 3 layers of drywall, thier studs&insulation, drywall and their paint. So i don't think there's leakage between houses.

Funny. A month after moving in we went to a homeshow where we found out about about all these things for the first time. If only we'd done this before so that we could have paid to have these upgrades done at build time since they would have been relativly cheep at that time instead of expensive upgrades now. Things like HE furnaces, whole house ventilation with heat-recover, better windows, extra insulation in the walls, etc.

Gas. I thought about buying the $20 water tank insulating blankets at home depot.

Blown cellulose stuff. R42 (or 32, can't remember). But one can always add more.

Down to floor.

I've seen a few websites and read many usnet postings. So far all the 'little things' i've found to do are pretty much the ones you mentioned. Is there another good source of things like the above that one can do?

The plan is to, sometime in the future, build a strawbale (or other highly efficient) house more out in the country with wind and solar generators. Possibly even go so far as to put in water reclamation facilites and whatnot. We'd love to be completly, or at least mostly, off the grid.

Thanks again.

[Michael Daly]

The biggest problem is getting to the leak if the whole whose is finished. An unfinished basement gets you to the place where many of the external connections (plumbing - like outside water tap, electrical, phone/cable etc), so you can close those. If you have a suspended ceiling try removing some panels near the outside walls and see how it looks.

You can get an airtight box and seal the cover for any electical outlet. Not as good as getting to the source of the leak, but adequate otherwise. Check the front and back walls for any obvious leaks - the external phone connector (sometimes a box) could be open. Don't plug a weeping hole in the brick though.

Holes are often made for external air conditioning line, phone/cable electrical service etc. Find and seal them from the outside if you can't get to the vapour barrier inside.

Ahhh... 20/20 hindsight - just think what your _next_ house will be like :-)

Keep looking - I can't think of any single source. Perhaps someone else can.

You and me both - I'm close to doing this, it all depends on finding a job in a place where I can afford the land. T.O. is toooo $$$$$.

Mike

[TAB Dude]

SNIP - Just FYI, this 'party wall' between townhouses is made of my paint, drywall, studs&insulation, 3 layers of drywall, thier studs&insulation, drywall and their paint. So i don't think there's leakage between houses. -

There could be a great deal of leakage in this wall. If there are any pipe chases, electrical runs, duct runs or other penetrations that go from the basement to the attic, the wall structure will act as a chimney pumping heat from the house to the attic. Have a contractor with a blower door come in a test your house. He can tell you how much your house leaks and where the serious leaks are.

TAB Dude

[Art Begun]

One place to look for energy leak is under the bottom row of siding. I often see huge gaps there. Check with an inspection mirror. If you see a gap it needs to be filled with backer rod and silicone. Will keep air in and bugs out.

[George E. Cawthon]

Sure, calculate the annual therms and cost of your gas now. Find out the efficiency of your current furnace and the efficiency of what you would replace it. As a ratio of the efficiency ratings, calculate the annual therms. You will probably find that your payout on a $3000 furnace would take forever. If you like your present furnace, forget it. The more efficient furnace will likely be more noisy.

[CBhvac]

And gas projected costs in a year, 2, 3, 5 years out.

Either a 80%, or a 90%..and its easy to find out if someone would post a model number...

Not forever, but longer than the unit will last.

Doubt that. Installed correctly, sealed combustion units are all but silent upon fire. The blower makes more noise than the burners.

[Martik]

The payback is negative if the (fuel savings - high maintenance costs) are less than the investment return on the $3000.

[kjpro]

As I agree with most of your posting, did you see he lives in Canada?

The difference in the higher efficiency furnace may pay off.

-- kjpro _-~-_>_-~-_>_-~-_>_-~-_>_-~-_>_-~-_>_-~-_>_-~-_>_-~-_>_-~-_>_-~-_>

( kjpro @ starband . net ) remove spaces to e-mail

Want it done yesterday? Or done right today, to save money tomorrow!!

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[kjpro]

Heat pump in Canada? I don't think that would be a wise investment.

-- kjpro _-~-_>_-~-_>_-~-_>_-~-_>_-~-_>_-~-_>_-~-_>_-~-_>_-~-_>_-~-_>_-~-_>

( kjpro @ starband . net ) remove spaces to e-mail

Want it done yesterday? Or done right today, to save money tomorrow!!

_>_>_>_>_>_>_>_>_>_>_>_>_>_>_>_>_>_>_>_>_>_>_>_>_>_>_>

[CBhvac]

Actually...lets get one thing clear. There is never a payback period. None. Ever.

You buy the unit....its saving you $XX a month. Big deal. You still have to pay to run it, and you still have to buy fuel for it. Unless you are using an old 1950 Chrysler Airtemp with a gas valve pressure thats so damn off its blowing black soot, and running the unit so hot its TR is about 100F above factory spec, and have been doing that for years, even a 94% wont really do much but lower the expense per month to use the unit.

Payoff periods are a sales technique that the public actually enjoys. I dont use them. Someone asks me what the payoff period for a new unit is, I tell them about 15 minutes after I hand you the bill....it will take that long to read the warranty to you and familiarize you with the controls, and for you to write a check....then of course, we pull out the States calculation sheet and show them what they might save....thats MIGHT.

If you have a $400 a month gas bill, and you put in a unit and its only using $200 a month, you STILL have a $200+ a month investment in the unit.

IF you have a gas unit thats using $200 a month and you put in a heat pump that eliminates your fuel bill, but raises your electrical by $100 a month, you still have $100 a month going into that machine.

Payoff? Depends on how you look at it. Some see it different than others.

[Oscar_Lives]

OK-- who left the sky light open? We got us an MBA in here now...

[CBhvac]

Dammit man..I handed YOU the tamper proof Torx and the driver...

[Michael Daly]

Yes all of us Canadians live in -60C temps 10 months of the year.

Reality - there isn't that much difference between northern US and Southern Canada. It's unlikely that the higher efficiency will pay off. I've done the numbers several times in the past and even the higher gas prices today won't make a difference.

Mike

PS - lots of heat pumps up here.

[Michael Daly]

That leak should be outside the vapour barrier. Better to fix the vapour barrier and let the insulation breath.

Mike