Opinions...will i save money???

[MeLikeUmFire]

I posted a couple days ago about the cost of supplemental heat with a infared heater. Want opinions:

house: 1976 typical colonial (all cut up) 2500 sq ft...4 bed rooms up. new windows, lots of insulation in attic...walls (whatever was put in in 1976) brick ext on 1st floor & alum siding on second floor

sometimes when it gets colder 25* or below i have a hard time getting the upstairs warm with the insert in the 1st floor family room.

Will i save $ if:
9:30 pm...cut t-stat to whole house to 58* (usually have it at 65*) furnace is 2005 comfort maker LP gas (2.29 gallon) 92% efficiency
9:30 pm....turn on infared heater in hallway upstairs...open 2 bedroom doors that need heat (with hallway and 2 bedrooms approx 650 sq ft)...set heater t-stat to 65*
4:45 am....have t-stat on whole house come on set to 65*

I figured out (with your guys help) that it would cost bout $1.45-1.60 to run the infared heater for 8 hrs at night continuously...i think it will not run continuously since i set the t-stat at 65*.

Would i save money doing this or not?

When house furnace has to go from 58* to 65* in morning am i wasting too much propane ($2.29 gallon) and electric (to run blower motor). how do i figure the cost to run my LP gas furnace with accounting for the electric blower motor...so i can compare the two (furnace operation vs infared heater for 8 hrs)

 

[rwhite]

I am going to have to follow this thread to see your solution. I pretty much have the same issue but upside down. I have a 3 story (sunken basement, main floor and loft) olde house. Insert is on the main floor and does a good job of getting heat to the loft. My issue is now a cold basement because the furnace doesn't come on. It stays about 58-60 degrees down there. So far the only solution I have is run a space heater or live with it. I have thought about adding a circuit and putting a few base board heaters in. Now I just kick on the furnace in the morning to take the chill off the whole house while the fire gets going then shut it down. Just doing that I have still cut my gas usage by 80%

 

[maverick06]

There are a lot of viarables here... probably hard to get a perfect answer. I speculate that:

YOU WILL

Because the electric heater costs lots more ($/BTU) to operate. BUT you are heating a much smaller area.

Previously, you heated the whole house, with an effecient heater. However, the heat was lost out of the whole house. As you were keeping unoccupied areas at temperature. Lower $/BTU, but more heat loss.

Now you will be heating a smaller area, at a more expensive rate. You hope to lose less heat, as you are only heating the area that needs it, not the whole house. Higher $/BTU but less heat loss.

You could caculate how much electricity the blower on the furnace uses. It may even be stamped on the furnace. I am not sure how to identify how much LP its using. The electric heater could easily be measured with a kill-a-watt. Do keep in mind that it will change day-to-day. Your losses will be much higher on a cold windy day, than on a mild-still day.

I suggest going for it. I have my daughter's room heated with an electric heater, but the rest of the house with the insert (and furnace as a backup).

You may find that heating th ebedrooms with individual electric heaters will work better. Some dont perform well on larger areas.

 

[Gary_602z]

Bet you will find that it will not shut of at 65 once the house temp drops a little.

Gary

 

[woodgeek]

You are really asking two questions....

1) How much will I save in propane by doing the setback from 65-58 every night?

The answer varies, but the usual numbers are ~6-8%. Take your annual propane bill and multiply it by 0.07. That is how much you will save in propane.

2) How much will it cost to heat the top of my house, or at least the hallway to 65...the answer is $1.50, or for 4 mo of winter, about $180. OR less if it doesn't run full out.

I suspect that the (2) will eat significantly into your savings from (1), and in the case it doesn't run much, you will still be cold up there.

Most folks who do setbacks invest in warmer bedding, nightcaps, robes and slippers for trips to the bathroom, etc.

A much more efficient approach is to put the supplemental heat where you want it...in the bed, not the hallway. Get some nice low wattage electric matress pads, and put those on timers.
You will be more comfortable and save a bundle.

 

[backpack09]

I have no $$ compairisons, but I have run an oil filled space heater in my kids bedroom and keep the house thermostat set at 62 at night. With the wood stove on the first floor, the furnace almost never turns on. Occasionally our bedroom will be drop into the 40s on a really cold night, the kids will be toasty, and the furnace will not turn on at all.

I recommend the oil filled radiators over an infra-red heater. IR heaters really only heat objects, and are fire hazards when you are sleeping as they can overheat nearby objects.

Oil filled radiators are cheap ($40) and keep a more constant heat level as the oil works as a heat sink.

Either way you look at it, any electric heater you use will use the same 1500 watts and generate the same amount of heat. There is no use in spending 200$ on a fancy unit unless you need the looks.

 

[pyper]

Here's something that might help in your decision making:

This is from high school physics: It takes more energy to keep something at a constant temperature than it does to let it cool off and then heat it back up later. This is independent of any insulation or any other factor.

So you'll definitely save propane by letting the house cool off at night.

The only exception to the rule above is if you have a heatpump with resistance "emergency heat" that comes on automatically at a certain temperature differential. In that case it *might* be cheaper to keep the house at temperature with the heat pump than to let it get cold and then heat it back up with resistance.

 

[Don2222]

Hello

Wood Pellets at $4.00 per bag is $1.33 to run it for 8 hours. So the best Solution is to install a wood pellet stove upstairs in the hallway!! Amen!!

A Window pellet stove is easy to install

What a deal!
http://providence.craigslist.org/hsh/2766552713.html

 

[rwhite]

I have been thinking about trying this (maybe a completly dumb idea). Figure out what the normal nighttime temp is for the area where the stove is (this is also the area where the thermostat is). Say it's 67 degrees. Set my programmable thermostat to come on at midnight and 5 in the morning for about 15-20 minutes. I would have to program the thermostat to about 70 degrees during those times. That would kick the furnace on and take the chill off the unheated areas. The rest of the day the thermostat would stay at 65.

 

[ironpony]

my personal opinion/experience
more than a couple degrees and it takes more energy
to recover the heat than maintain it
everything in the house cools down and it needs warmed up

 

[semipro]

It takes more energy to keep something at a constant temperature than it does to let it cool off and then heat it back up later. This is independent of any insulation or any other factor.
.

I believe this is correct.
Its occurs because heat loss rate is a function of temp difference.
That is, the bigger the temp difference between two mediums, the faster the heat transfer.

So your houses loses proportionally less heat if you let it cool off at night where the internal temp gets closer to the external temp.

If I'm not mistaken, the most energy efficient thing you could do is let the temps fall as far as you can where you can still bring the house back up the desired temp by the time you get up.

Oak Ridge National laboratories did some good work supporting the use of set-back thermostats in houses based on this principle.

 

[maverick06]

+1

Its very simple, yet huge numbers of people get it wrong.

at a specific temperature difference between inside and outside, you will lose a certain number of BTU/hr.

If you lower that difference (by letting the house cool off) you will lose fewer BTU/hr.

So at the end of the day, your house needed less heat! (same is true for the summer).

now, when you have different types of heat that cost different amounts, its makes it more challanging (I will get my house a little warmer with my insert before I go to bed, so that it has longer to cool off before the heat kicks in. I wouldnt do this with the thermostat, but because wood is so much cheaper than oil/electricity, its the economical choise for me).

 

[woodgeek]

Yup. For nighttime setbacks, the general guideline is 1% savings per °F setback, 7% for the OP case. HPs are often cited as an exception, although to a large extent this problem has been alleviated in the latest generation of thermostats. Since the OP does not have a HP, it is a non-issue.

 

[jebatty]

Do something completely (almost) different. Forget about heating the hall and bedrooms, because in a few minutes everyone will out of bed, down the hall, and the space again is unoccupied. It's a "waste."

We heat our house with a wood stove. Each night we let it burn out. Bedrooms and bathrooms are on the opposite side of the house from the wood stove. When stove is heating, living room, eating area and kitchen are about 68-72, bedrooms and bathroom about 60-65; nighttime main house may cool down to 60, bedrooms and bathrooms 50-55.

Solution: electric heat only for the bathroom, keep the door shut, exhaust fan on if bath or shower. Bathroom is toasty warm; everyone gets the warmth he/she needs; forget about modesty, do your duties. Bathroom (kickspace) heater, on a wall timer, in about a 100 sq ft space only needs to be on for about 10-15 minutes, heater shuts offs by the timer. Everyone out and about. About $0.15 per day average for electric during the cold months.

 

[SolarAndWood]

What is your cost of wood? Is an add on furnace an option? Have you dealt with all the easy heat loss issues?

We needed supplemental heat with a 2 cubic foot stove. Doubling the size of the stove eliminated this need other than a small heater in the bathroom. We had a lot of motivation to make wood work though as propane is a buck more a gallon here and our electricity isn't cheap either.

 

[semipro]

Do something completely (almost) different. Forget about heating the hall and bedrooms, because in a few minutes everyone will out of bed, down the hall, and the space again is unoccupied. It's a "waste."

We heat our house with a wood stove. Each night we let it burn out. Bedrooms and bathrooms are on the opposite side of the house from the wood stove. When stove is heating, living room, eating area and kitchen are about 68-72, bedrooms and bathroom about 60-65; nighttime main house may cool down to 60, bedrooms and bathrooms 50-55.

Solution: electric heat only for the bathroom, keep the door shut, exhaust fan on if bath or shower. Bathroom is toasty warm; everyone gets the warmth he/she needs; forget about modesty, do your duties. Bathroom (kickspace) heater, on a wall timer, in about a 100 sq ft space only needs to be on for about 10-15 minutes, heater shuts offs by the timer. Everyone out and about. About $0.15 per day average for electric during the cold months.

This is almost exactly what we do. The bedroom is cool but its great for sleeping.