I have a 1916 bungalow, approx 2000 sq. ft that uses forced air as a heat source.
I am working on remodeling the original below grade garage into an office – apppox. 440 sq ft. Since I need to pour a new slab for this section, I thought about using radiant heat as opposed to adding a trunk to the forced air system.
This space will open out onto a 250 sq ft below grade terrace, so I will have an 8′ by 12′ opening with french doors opening up to that. The basement walls are concrete block, no insulation on the outside. one thought was that I could use the radiant system under the terrace floor as well, as an ice and snow melt system.
I also have approx. another 400 sq. ft of basement area I would like to add the radiant to, with a total of three zones excluding the terrace.
I live in NW Indiana right outside Chicago, so it gets pretty cold in the winter. It also gets hot in the summer, so I would still need to deal with an air conditioner source for the office in summer. The house currently has central air.
In general, would radiant heat in a basement slab make more sense than upgrading my forced air and adding zoned ducts?
Replies
If you heat those floors, you'll hang out in your office all winter... never go into the rest of the house. Your dogs will also live in there, laying on the floor. You have a relatively high heat-loss climate, so be sure to have a good radiant contractor run the calcs for you. A floor can only produce a certain number of BTUH, so you may need supplemental radiators.
Do you know if I can I run radiant for the office floor and the outdoor ice melt off the same heat source?
the outdoor ice melt off the same heat source
A person could actually probably make a pretty good case for a passive solar collector for the terrace snow melt system. Even as far north as you are, the hours of sunshine are still high enough to run, say, two 4x8 panels.
Part of the reason why is that for the snow melt, you need only to have above-freezing temps in the slab. 45º or 50º water should (barely) suffice for that. That allows for collectors running at lower efficiencies (temp or volume) than domestic water or heat use needs.
Might not fit in with the rest of the style in the neighborhood, or it could be a great excuse for a shed, over there, yeah, in the that sunny spot . . .
Just a thought.Occupational hazard of my occupation not being around (sorry Bubba)
And a good thought it is.Just so happens that we are designing a 20 x 30 carport with a flat roof. The entire structure is going to look like a pergola, with the flying rafter tails to mimic the rest of the house. Stone supports with craftsman-like columns supporting the entire roofing structure.Perhaps I could incorporate the solar panels into this roof, where they would be less unsightly. Worth looking into that's for sure.Would there be some kind of backup system incorporated in case we get too many grey days?
Perhaps I could incorporate the solar panels into this roof, where they would be less unsightly.
Solar water heating panels? Always wanted to try those. Always figured a solar water heater setup that travelled through a tankless nat. gas heater would be the way to go for DHW.
So even if the solar water heater tank doesn't get it up to 120, the tankless heater takes it the rest of the way.
Not exactly sure of how to combine it with a radiant floor setup, but sure it could be done.
jt8
There is no revenge so complete as forgiveness. -- Josh Billings
Would there be some kind of backup system incorporated in case we get too many grey days?
Well, for a domestic system, that's easy enough--it makes me wonder how low a t-stat setting a person could make on a small electric heater (in a domestic system, it's kind of nice to use a large, already well-insulated wh as a storage tank).
The pergola would be a neat install (especially how you'd get some shade come summer for "free") except with a foot or tow of snow on the collectors they don't soak up much sunlight . . .
I'd guess (not having any of my crib sheets with me) that your "optimal" angle is around 45º for a collector--less than ideal for a pergola. I may have to go dig out some of the dustier tomes tonight for better answer.
With a good, deep (think 3-4 coats) indigo paint in the collector, there's still a pretty good gain even at 75% overcast. It's the light you can't see that does the most good, as long as we don't need hw temps.Occupational hazard of my occupation not being around (sorry Bubba)
Something like the attached?
jt8
There is no revenge so complete as forgiveness. -- Josh Billings
I am even more intrigued now. My bggest question though is one of cost. I wonder what kind of costs I'd be looking at to incorporate passive solar and what kind of payback I would see.
See if you can get Mike Smith's attention. I believe he installed solar water heaters on his own home. He might be able to give you an idea of their practicality in your situation as well as costs.<!----><!---->
If only we were made of money, we could size a solar water heating system to heat the garage/basement radiant system as well as the driveway/sidewalk glycol one. And then during the remaining 3 seasons of the year, we use the added hot water production on the in-ground pool...all the while thumbing our nose at the utilities and their rising rates. ;)
<sigh> What a shame we aren't made of money.
But get Mike's attention. He should be able to give you some hard facts rather than my wishful thinking. WAG: A basic solar water heating package starts in the $2-5k range (at which price you might be doing the installation).
DomesticHotWater production accounts for a substantial portion of annual energy consumption. Add the radiant floor to that equation, and a reliable solar water heating system might pay for itself in as little as 5 years.
And while we're throwing ideas at you... There is also geothermal heat pumps. I believe there are combination units were are capable of being used in forced air and hydronic. The geothermal unit could therefore be sized to include the entire house. But the pricetag goes up with this option. While considered by many as the MOST energy efficient system available, the geothermal is also one of the most expensive ones.
And on that note, I think its time to hit the sack...
jt8
There is no revenge so complete as forgiveness. -- Josh Billings
Thank you John. I will look into this further and ask Mike about it as well. I owe him a book I promised to send two weeks ago and haven't. I'll drop a note in with that package.
"Do you know if I can I run radiant for the office floor and the outdoor ice melt off the same heat source?"
Sure you can. It's just another zone. One good way is to use a plate-type heat exchanger to separate the glycol loop (snow melt) from the heating system. That way you do not need to run glycol through the whole thing.
Also, the plate exchanger prevents thermal shock from the cold return water if you were to use a conventional boiler that cannot handle it.
Edited 1/25/2005 5:24 pm ET by csnow
What's fuel source is available?
If gas, it's a no-brainer to add a self-contained RFH system running off it's own water heater. Eliminates a lot of the controls and valves.
Snow-melt can work, realize that the BTUs required for that can up the system requirements to make the water heater oversized for what you might need without the snowmelt. Certainly put it on a separate zone.
A hundred ways to skin this cat, and RFH sounds like a good one to me.
No ductwork, etc.
If the underside of the first floor is exposed, you might want to consider doing a staple-up and converting the first floor living space to radiant as well.
One of those cases where you've run the first 25 miles of the marathon...why not do the last mile as well.
ah yes the beauty of SIM systems
View ImageRBean
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That's one thing I never did understand- why go to all the bother of buying expensive glazing and expensive insulation if you're just going to pour heat outside whenever it snows?!?
Unless you've got a bad back or some other medical condition, what's wrong with a shovel? Most of North America could use the exercise- heck, even the 80 year old lady next door shovels her snow! And if you can't or don't want to, pay the kid down the street and teach them the value of a buck- they probably need the exercise even more than you do!
What's the point of mandating high insulation levels in new houses in building codes if you permit people to waste heat on a grand scale in snow-melting systems? A good use for waste heat from a cogeneration facility maybe- but here you're burning a huge amount of natural gas to melt that snow...
Some people value the security, safety, health, reliability, and convenience of having a <!----><!---->SIM<!----> system…just one mans values.
In my case I travel alot and having clear driveways is part of our over all security strategy.
We have seniors and small children visit our home and their safety is our concern.
1994...I was rear ended by semi truck hauling fuel - it was a very bad accident and I will never be the same. Thanks for reminding me.
We never had to call the kid down the block or a landscaping service to shovel at 4:30 in the morning.
We can (and do) turn it on and off at our convenience.
When I am in town, I walk or ride my bike to my office or to do errands...we refuse to spend anytime in traffic jams idling our engines or burning fuel warming up the vehicle for trips to the convenience store. We maintain our boiler for the highest combustion efficiency; run our home at the lowest comfortable level etc…we do that so we can run our system.
So those are my values ...
Peace.
RBean
http://www.healthyheating.com
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Edited 1/24/2005 9:28 pm ET by RB
Yeah, I know, it's a snotty-nosed criticism about how others use energy, and I'm sorry for insinuating that anyone who uses energy in this way is reckless- it's totally unfair of me to make that kind of judgment. By no means do you sound like a reckless energy consumer. But the energy required to melt a significant snowfall is very, very significant...
Some things we can "afford" monetarily, we still shouldn't be permitted to do- until energy is charged at its FULL cost in all respects. Personally, I think that heating an outdoor driveway in wintertime is one of those things. Electric resistance heat as a main source of comfort heating is another. And I still question why building codes would permit these kinds of installations and yet mandate all sorts of expensive energy conservation measures.
I understand your arguement about energy consumption, however there needs to be a line that is drawn someplace, For example I use mostly floresent lights and I really conserve energy as much as humanly possible. (super insulated home) Yet I'll turn on the sidewalk melting equipment at every snow fall. At night I sit in the living room with only the light from the TV screen to illuminate the room with every other lite in the house turned off.. Maybe I shouldn't watch TV since that consumes electricity.
I have a whole bunch of exterior lights around the house but they are almost never used except for events (can't call them parties)
My electric bills (the sidewalk is electric) is never over $60.00 a month and if I ever finish building this house and stop using all those power tools in the basement to build it the bill will go down to about $30.00 a month!
Finally regarding electric heat, I have yet to see a comparison between say electric water heaters and gas water heaters.. oh sure, they show that the gas one costs this much per month and the electric one costs this much,,. but they don't include the calculation of having a 4 inch exhaust pipe in the basement open to the outside 24/7/365 sucking that heat you just paid for out..
There is a TV program called myth busters that proved having a fire burning in a fireplace cost you more heat while it was burning than it generated. (goes against common sense doesn't it?) That didn't measure the heat loss of having a fireplace in the first place.. (Note I said fireplace and not stove)
living room with only the light from the TV screen to illuminate the room
You probably would have a slightly higher "comfort" (eye comfort, that is) value by adding a couple of 15-20w fixtures in the vack corners opposite of the TV. It's not quite enough light to reflect glare back except on the darkest tv scenes--but, it will reude eye fatigue that occurs when you shift focus from the bright screen to the darker surroundings.
Reducing eye fatigue helps a person rest & relax. Better rested people are more productive. Increased production benefits all. Yep, I think "society" can spend an extra 30-40w to make you more productive <g> . . . Occupational hazard of my occupation not being around (sorry Bubba)
Just use a couple of old 20" TV's.
In my case, the snow melt would be used for a terrace that is 5.5" below grade. While only 200 sq. ft. the thought of shoveling snow upward is not too appealing. I figure if I am going to put in radiant for the new basement slabs, why not add a small branch to melt the terrace. The new drive way, sidewalks and others hard surfaces outside will get done with a shovel and snow blower.
Excellant question!
Why melt when you can shovel?
Ever see the number of people who die every year with a snow shovel in their hands? Scary! Ignore those who slip and break a hip or suffer from frost bite,, they aren't worthy anyway! As for those wooses who use snow blowers and wind up chopping hands off unplugging them, they should have done it by arm and muscle power.. After all when discussing physical fitness the experts always tell you to over work yourself and do it when you are cold! In addition they highly recommend that you do it when you are stressed trying to get to work and it is always best to excersice at irregular intervals and for just part of the year! Always the best way to get into condition..
I live in Minnesota and we get feet of snow sometimes, what should we do with it? if you toss it on the side of the driveway it causes snow drifts the next day when the wind blows and then you need to back out and reshovel.. Winter here is serious business, 8, 9, 10 months of the year (well,... maybe that's a slight exageration <G>)
My driveway is 30 feet wide and 130 feet long if I were to plow on occasion the sides of the driveway would be over 10 feet high! Long way to toss snow!
I've lived in this state most of my adult life, As an adult I'm proud of the fact that I've never shoveled and never intend to shovel!
Edited 1/25/2005 1:51 pm ET by frenchy
that is even more awesome to see when the snow is deeper :)
jt8
When women love us, they forgive us everything, even our crimes; when they do not love us, they give us credit for nothing, not even our virtues. -- Honorý de Balzac
Thats a good idea, thanks.
If you want to use radiant for interior and exterior, you will need a boiler, a heat exchanger, and a glycol based system for the outside heating. A neighbour of mine has the same system installed on his driveway down the street. I have to admit when I'm shovelling I gaze at his clean driveway with envy! But the basement utility room of his house looks like the engine room of a small ship what with all the pipes, tubes, etc.
Here's my favorite boiler room picture...the modern pre assembled package systems really clean up the space...wouldn't you agree?
View ImageRBean
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Nice installation! I'm sending this link to my neighbour. Thanks.
Here's the load Calcs, 1.5"/hr snowfall, 0 deg F temp, 5 mph wind, insulated slab
Assumes you'll tolerate some snow built up with eventual clearing after it has stopped snowing. We call this a Class I system which should handle about 75% of the loads...if you want a more aggresive system let me know ... you have one more free ticket left. Danfoss makes a small preassembled control panel perfect for your radiant and SIM application.
View Image
RBean
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Edited 1/25/2005 3:39 pm ET by RB
What shape is your current forced air furnace in?
The reason why I ask is, your loads and temperatures are creeping into small boiler territitory.
If the existing furnace is getting long in the tooth then it opens up a number of good options.
Let us know.
RB
RBean
http://www.healthyheating.com
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RB,
any idea what it costs to run the heat under that driveway ?
just curious
carpenter in transition
Operating cost are all over the board - depends on weather conditions, price of fuel and how we operate the system.
It has been as low as $100 to as high as $500 per month...its about as consistant as the weather. LOL
RBean
http://www.healthyheating.com
http://www.healthyheating.com/blog