How low can YOU go?

[Hawkshot99]

And who can explain this phenomenon correctly to Marc Engineer and earn a gold star?

:dunce:

The furnace is run a little here, a little there to keep a constant. Rather than letting it slack off for the day, then having to work real hard when the time comes to kick it up to the high temp.

Just like a steady foot on the accelerator will yield better gas mileage than someone who stomps on it, then lets off, then stomps on it.....

 

[Marc]

Have you checked out Masonry Heaters? We want to put one in when we build a house. You need an open floor plan, but you'll only burn 3 cords instead of the five.

I've seen those installed in homes before. Wouldn't be an option in the house I'll probably end up in (long story) however I do like the idea. I'd be wary of cracking in that much masonry though, and I've also read you need to use wood with high surface area to mass ratio because they're meant to burn hot and quick, which would mean a lot of splitting. The other drawback is how long they take to heat up, since with a large amount of thermal mass in the form of masonry comes a large amount of thermal inertia. I'd see inconveniences with January thaws and early frosts or early spring.

A lot of woodstove installations use similar principles, for instance, my parents' woodstove sits on a large brick hearth which extends floor to ceiling behind the stove. This also provides a large thermal inertia and continues to radiate long after the fire in the stove has died out.

 

[ccskier]

You are all crazy. I keep my house at 70 year round. Central A/C set at 72-74 in the summer. Heat on at 68-70 all winter. We have gas forced hot air. Wife and baby are home during the day so we never get a break. I personally keep the window cracked and fan going in bedroom year round. Maybe, I could save a few buck. The ironic thing is that I just paid my gas bill before checking the AZ, last months bill was $30. Looked at last Jan/Feb when baby was first born, $335- that hurts.

 

[snoseek]

Is a passive solar heating design feasible in new england anyone know?

 

[severine]

And who can explain this phenomenon correctly to Marc Engineer and earn a gold star?

:dunce:

To be fair, I understood the why of how a consistent temp is more energy-efficient... It just always surprises me how many people are suckered into the mentality that you'll save a few bucks by turning down the heat during the day. Every store I can think of sells those programmable thermostats as a way to save money. But it never works out that way and once you think about it, you understand why. We just went the further mile of spending two winters testing it in the field to see the anticipated results.

That said, we now also do the budget pay plan for natural gas. And even though natural gas has gone up significantly over the last few years, our bills keep dwindling. I haven't totally figured out why as the set-back thermostat experiment was 6 years ago and a couple years before we decided to do the budget plan. The plan is re-evaluated every May and adjusted accordingly by Yankee Gas. 2 years ago, we were paying $155/month. Last year was $145/month. This year? $135/month. I've been home more in the last 10 months than I was in the 5 years preceding that and I've done a heck of a lot more cooking, too (gas stove). The only thing I can think of that's significant is I used to take 1 very hot shower every day for about 10-15 minutes and now, with 2 kids and no free time, I'm down to 2-3 showers a week.

 

[severine]

Is a passive solar heating design feasible in new england anyone know?

My hippy friends (as Brian calls them) seem to think not. You have to have a really good southern exposure and enough sunny days, from what I understand, having no real knowledge on the subject, of course. But one of my friends was telling me about her very green neighbor who has such a system on his house and while he's not off the grid, he only pays $25/month for electric. He may be heating his house with that as her house (built around the same time) had electric heat, too.

 

[snoseek]

My hippy friends (as Brian calls them) seem to think not. You have to have a really good southern exposure and enough sunny days, from what I understand, having no real knowledge on the subject, of course. But one of my friends was telling me about her very green neighbor who has such a system on his house and while he's not off the grid, he only pays $25/month for electric. He may be heating his house with that as her house (built around the same time) had electric heat, too.

From what i understand most houses in the old days were built with heating from the sun in mind, and in the last 40 years contracters stopped doing this. If you have a good southern exposure, then its as simple as a couple big windows to let in the sun, a large maybe stone surface to heat and hold the warmth, and a overhang that keeps the high angle summer sun rays out so you don't sweat your A$$ off in july. there is other stuff like radiant floor heating systems, but i don't know too much other than it involves the sun. question is is there enough sun in new england, i think maybe yes.


www.motherearthnews.com is a pretty interesting hippy read that always seems to have info on this kind of stuff, but they always use examples of hippies somewhere in the desert. any vermont hippies want to chime in?

 

[severine]

Unfortunately, it's even longer ago than 40 years when they started getting away from southern exposures. Our house (which, granted, is a 3 family house that was built as a 2 family house) has all of 2 south-facing windows in the apartment. One is in the bathroom, the other in the bedroom. Now, even though it's poorly designed, you can tell a difference on sunny days in the bedroom (which also has a west facing window). Quite a bit of heat will build up and actually stay in that room, in spite of the draftiness. But I'm wandering... what I'm trying to say is that I don't think the thoughtfulness for taking advantage of the sun and natural heating/cooling has been around for quite some time now. Which is a real shame.

That neighbor of which I spoke? I think he has some solar panels to help out.

 

[snoseek]

I think they can use solar panels to heat water for use and for radiant floor heating. My girlfriend is a "green" designer, but is away right now. She knows a real real lot about this stuff, i only pick up about 1/2% by overhearing her conversations while thumbing through the latest issue of powder.

 

[hammer]

And who can explain this phenomenon correctly to Marc Engineer and earn a gold star?

:dunce:

Actually, I'd like to read the explanation...from a simple energy/heat transfer perspective, I'd think that you would want to keep the temperature at as low of a level as possible. Yes, it will take some time to heat the house back up at the end of the day, but would the additional time the heater is running be more than what it would have run to maintain the higher temperature throughout the day?

I wonder if this would be a good experiment for the Mythbusters folks to do...

 

[Marc]

Actually, I'd like to read the explanation...from a simple energy/heat transfer perspective, I'd think that you would want to keep the temperature at as low of a level as possible. Yes, it will take some time to heat the house back up at the end of the day, but would the additional time the heater is running be more than what it would have run to maintain the higher temperature throughout the day?

I wonder if this would be a good experiment for the Mythbusters folks to do...

Well, the problem is it is a much more complicated an issue than it seems at face value and greatly depends on the house's geometry, insulation, windows, exposure, heat generation and distribution system, thermostat location, zone layouts, etc.

However, the basic concept for a house that requires greater energy to raise to a certain temperature after cooling vs maintaining a certain temperature is this:

The rate at which heat transfers through your walls, windows, roof, foundation, and gaps in construction depends on the temperature gradient across the wall or barrier (inside vs outisde temperature). In the situation where one maintains a higher arbitrary temperature throughout the day, the cycle time of the heat can be such that the heat has a chance to distribute more evenly throughout the house in between periods of heat generation.

So if your house loses X units of energy per hour at H temperature and Y units of energy per hour at L temperature, and your house lost energy uniformly across all surfaces, X would naturally be greater than Y.

Letting your house lower to temp L during the day requires 12Y energy to maintain L (assuming a 12 hour period) and 12X to maintain H. The energy to raise the house from L to H we'll say is D+ units of energy, which, according to the wisdom of lowering your heat, would be more or less conserved by allowing your house to lower to L (in that period, no heating is required, the savings we'll call D-). So this wisdom leads to the assumption that the total energy savings i s 12X - 12Y = S units savings.

Where this can be a fallacy is the process of increasing the temperature of ones house can be more (sometimes much more) inefficient that maintaining a temperature. So much so that the energy to raise the internal temperature D is not only more than D-, but more than even S plus D-. The reasons for this inefficieny come from the factors I mentioned above... uneven heat distribution and house geomtery and environmental factors lead to hotspots throughout the house encountered only when increasing the houses internal temperature and not as drastic when simply maintaining it. These hotspots occur and persist, and are areas where lots of energy is lost while other parts of the house, most notably where the thermostat is located, is still waiting for the heat to be distributed there. So in certain cases, it can be more economical to let your house cool in the day and heat back up when it is populated again in the evening, and other times its not.

The real kicker is the only way to find out is to experiment, and even that can be misleading because of independent variables very hard to control (temperature, humidity, wind and solar radiance).

Everyone got that?

 

[bvibert]

y=mx+b?

 

[hammer]

Well, the problem is it is a much more complicated an issue than it seems at face value and greatly depends on the house's geometry, insulation, windows, exposure, heat generation and distribution system, thermostat location, zone layouts, etc.

However, the basic concept for a house that requires greater energy to raise to a certain temperature after cooling vs maintaining a certain temperature is this:

The rate at which heat transfers through your walls, windows, roof, foundation, and gaps in construction depends on the temperature gradient across the wall or barrier (inside vs outisde temperature). In the situation where one maintains a higher arbitrary temperature throughout the day, the cycle time of the heat can be such that the heat has a chance to distribute more evenly throughout the house in between periods of heat generation.

So if your house loses X units of energy per hour at H temperature and Y units of energy per hour at L temperature, and your house lost energy uniformly across all surfaces, X would naturally be greater than Y.

Letting your house lower to temp L during the day requires 12Y energy to maintain L (assuming a 12 hour period) and 12X to maintain H. The energy to raise the house from L to H we'll say is D+ units of energy, which, according to the wisdom of lowering your heat, would be more or less conserved by allowing your house to lower to L (in that period, no heating is required, the savings we'll call D-). So this wisdom leads to the assumption that the total energy savings i s 12X - 12Y = S units savings.

Where this can be a fallacy is the process of increasing the temperature of ones house can be more (sometimes much more) inefficient that maintaining a temperature. So much so that the energy to raise the internal temperature D is not only more than D-, but more than even S plus D-. The reasons for this inefficieny come from the factors I mentioned above... uneven heat distribution and house geomtery and environmental factors lead to hotspots throughout the house encountered only when increasing the houses internal temperature and not as drastic when simply maintaining it. These hotspots occur and persist, and are areas where lots of energy is lost while other parts of the house, most notably where the thermostat is located, is still waiting for the heat to be distributed there. So in certain cases, it can be more economical to let your house cool in the day and heat back up when it is populated again in the evening, and other times its not.

The real kicker is the only way to find out is to experiment, and even that can be misleading because of independent variables very hard to control (temperature, humidity, wind and solar radiance).

Everyone got that?

After carefully reading this, the answer is "it depends".

I still think Mythbusters ought to do an experiment on this.

IIRC there was an episode where they checked whether it was better to leave flourescent lights on or to shut them off...the end result was that you should shut the lights off. The extra energy to turn the bulb on was only enough to make a difference if you kept the lights on for about 20-30 seconds or so.

 

[Marc]

After carefully reading this, the answer is "it depends".

I still think Mythbusters ought to do an experiment on this.

IIRC there was an episode where they checked whether it was better to leave flourescent lights on or to shut them off...the end result was that you should shut the lights off. The extra energy to turn the bulb on was only enough to make a difference if you kept the lights on for about 20-30 seconds or so.

Even if Mythbusters were to do an experiment, it wouldn't mean anything for your house, unless you lived in the one they used for their experiment.

And most of the stuff the Mythbusters test, btw, can be conclusively answered to a high degree of certainty just by talking to the right knowledgable experts. That wouldn't make for entertaining TV, however.

 

[marcski]

I think the most energy efficient heating these days is radiant floor heating....especially if you're building new construction. While the initial cost is more, once the house is at temp, it costs very little to heat, plus, makes the toes nice and toasty.

Also, wood stoves are nice, add ambiance and all, (and yes, I'm a slight pyro and totally enjoy them, although, we only have a fireplace, which I do use in the winter), they are not very ecologically friendly. Besides cutting back trees, they add lots of soot into the environment....and you get those low lying "clouds of smoke" in the valleys during cold months.

 

[Marc]

I think the most energy efficient heating these days is radiant floor heating....especially if you're building new construction. While the initial cost is more, once the house is at temp, it costs very little to heat, plus, makes the toes nice and toasty.

Also, wood stoves are nice, add ambiance and all, (and yes, I'm a slight pyro and totally enjoy them, although, we only have a fireplace, which I do use in the winter), they are not very ecologically friendly. Besides cutting back trees, they add lots of soot into the environment....and you get those low lying "clouds of smoke" in the valleys during cold months.

Actually, newer woodstoves burn very efficiently, and do not emit a lot of carbon (soot), particularly the newer stoves incorporating catalytic converters. Only during start up do they tend to burn incompletely and inefficiently.

If you practice the selective or perpetual yield method of woodcutting, you only take from the land what can be regenerated in the following season (like I mentioned, about 1 cord/acre/year) and take only either the older, mature trees whose growth has slowed considerably or the irrepairably damaged trees or timber (dead fall, broken canopies, etc).

In this way, when you burn them and produce CO2, you are not producing much more that would have been released over time in the decay and composting of the tree were it to fall where it was cut, and the new growth replacing the vacated space and the CO2 absorbed will give the net addition of more or less zero to the atmosphere.

So if done correcty, burning wood in an efficient stove or furnace is remarkably envirnomentally friendly.

 

[marcski]

Actually, newer woodstoves burn very efficiently, and do not emit a lot of carbon (soot), particularly the newer stoves incorporating catalytic converters. Only during start up do they tend to burn incompletely and inefficiently.

If you practice the selective or perpetual yield method of woodcutting, you only take from the land what can be regenerated in the following season (like I mentioned, about 1 cord/acre/year) and take only either the older, mature trees whose growth has slowed considerably or the irrepairably damaged trees or timber (dead fall, broken canopies, etc).

In this way, when you burn them and produce CO2, you are not producing much more that would have been released over time in the decay and composting of the tree were it to fall where it was cut, and the new growth replacing the vacated space and the CO2 absorbed will give the net addition of more or less zero to the atmosphere.

So if done correcty, burning wood in an efficient stove or furnace is remarkably envirnomentally friendly.

Yes, my bro has a very nice newer wood stove with the catalytic converter, and if you're going to use the wood stove as your primary heating source, you're going to need a few cords each winter. But I won't argue with you Marc as I'm sure you have more scientific knowledge regarding these things...and you might mistake me for a gopher and try to blow me up!

 

[Marc]

Yep, depending on the size, layout and insulation of your house... my folks use a woodstove as their primary winter heat source and burn about three - five cords/winter. I've cut wood with my old man for years on his 5-6 acre wood lot, and theres more hardwood there now then he started taking wood off the land near thirty years ago.

Basswood in particular likes to grow up in a vacated coniferous space it seems, and grows fast!

The last several winters, I've helped cut only dead or dying trees and just that is plenty to keep going for a whole winter.

I tried to land that last big white oak we cut on top of a gopher hole, but missed. Varmint.

 

[Marc]

Actually it was probably a woodchuck hole.

 

[tjf67]

Well, the problem is it is a much more complicated an issue than it seems at face value and greatly depends on the house's geometry, insulation, windows, exposure, heat generation and distribution system, thermostat location, zone layouts, etc.

However, the basic concept for a house that requires greater energy to raise to a certain temperature after cooling vs maintaining a certain temperature is this:

The rate at which heat transfers through your walls, windows, roof, foundation, and gaps in construction depends on the temperature gradient across the wall or barrier (inside vs outisde temperature). In the situation where one maintains a higher arbitrary temperature throughout the day, the cycle time of the heat can be such that the heat has a chance to distribute more evenly throughout the house in between periods of heat generation.

So if your house loses X units of energy per hour at H temperature and Y units of energy per hour at L temperature, and your house lost energy uniformly across all surfaces, X would naturally be greater than Y.

Letting your house lower to temp L during the day requires 12Y energy to maintain L (assuming a 12 hour period) and 12X to maintain H. The energy to raise the house from L to H we'll say is D+ units of energy, which, according to the wisdom of lowering your heat, would be more or less conserved by allowing your house to lower to L (in that period, no heating is required, the savings we'll call D-). So this wisdom leads to the assumption that the total energy savings i s 12X - 12Y = S units savings.

Where this can be a fallacy is the process of increasing the temperature of ones house can be more (sometimes much more) inefficient that maintaining a temperature. So much so that the energy to raise the internal temperature D is not only more than D-, but more than even S plus D-. The reasons for this inefficieny come from the factors I mentioned above... uneven heat distribution and house geomtery and environmental factors lead to hotspots throughout the house encountered only when increasing the houses internal temperature and not as drastic when simply maintaining it. These hotspots occur and persist, and are areas where lots of energy is lost while other parts of the house, most notably where the thermostat is located, is still waiting for the heat to be distributed there. So in certain cases, it can be more economical to let your house cool in the day and heat back up when it is populated again in the evening, and other times its not.

The real kicker is the only way to find out is to experiment, and even that can be misleading because of independent variables very hard to control (temperature, humidity, wind and solar radiance).

Everyone got that?

Yeah turn the heat down during the day and at night and you will save money.