Ask The Sietch – Easy Cheap Solar Heat

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Got this question a while ago.

Need help! Our fuel bill is $700 per month. Married empty nesters on modest income from Wisconsin U.S.A. Cannot afford gas to run our in-floor heating for house and new dog kennel.
how can we build cheap solar heat for us and new kennel. ?

Well J, you are in luck my friend. You have two things going for you right now, you have radiant floor heating, and you have a very high fuel bill.

Lets take these one at a time.

Radiant floor heating:

how radiant flooring heats your home

You may not know this but radiant floor heating is probably the most efficient way to deliver solar thermal energy. For those of you not in the know radiant floor or under floor heating is when you heat your home with heat that radiates up through the floor. There are several different types of radiant flooring.

Thick slab:

thick slab radiant floor

This is where you pour a thick slab of concrete over a series of flexible plastic tubes. These tube are later filled with hot water to heat the home. The tubes are made of a type of plastic that lasts forever, is very flexible, and also transmit heat well. Radiant floors used to be made from metal pipes, this didn’t work out so well, the new plastic system work much better and last a lot longer.

The reason why you use a thick slab of concrete is because the heat from the pipes gets trapped in the concrete and is released slowly and evenly into the room. This eliminates hot spots, as well as making that first step out of bed on cold mornings much more enjoyable. It also heats the room from the bottom up, which feels better. it also reduces the dry air feeling of forced hot air and the cold spots of radiators.

Thin slab:

thin slab solar thermal

Thin slab is the same as thick slab but it uses a much smaller slab of concrete. Better for upstairs floors or for retrofits where you cant fit a thick slab system. They work very well but with a smaller thermal mass (the concrete) they are not as efficient.

Below floor:

between joist radiant floor

If you have an existing home and want to install radiant floor heating and also happen to have exposed joists in the basement you can retrofit your home with below floor radiant heat. You basically take the flexible plastic hose and staple it under the floor. You then place special metal reflecting plates over the pipes to “bounce” as much heat upwards towards the room above as you can.

So you know all this about your own system, what you might not know is how well you can tie solar thermal into this system. It doesn’t matter where the hot water comes from, it just needs to get into the pipes that run under your floor.

Right now you must have a hot water tank that holds the hot water (the hot water you are burning fuel to create right now), so you would call up your local solar thermal installer and get them to build you a solar thermal system that ties into that tank, the hot water would be coming from the sun, and you would not need to burn fuel to create it. You already have the pumps, you already have the storage, you just need the panels and a pipe run to the tank. Pretty easy right!

solar thermal panels
Typical solar thermal panels mounted on a flat roof, if your roof is tilted you will not need the racking.

solar thermal diagram
This is a technical diagram of how the system would work.
Your Giant Bill:

You probably think that I am crazy listing your huge fuel bill as a positive point. But here is why it is good, your large bill gives you a very strong motivation to do something about your problem. It would be easy to install a solar thermal system that will replace 50-80% of your heating costs. That means that if you pay 10,000 dollars on a solar thermal system (you can and will find them cheaper, make sure you do your research to make sure you are getting a good product) and it saves you 500 dollars a month, well you can see it will pay for itself in just a couple of years.

You may opt to buy a very modest system (one or two panels with a small solar driven pump for $1,000 – $2,000 ) just to heat your kennel. Either way you can offset a significant portion of your bill with a relatively minor investment in solar thermal heating.

Good luck!

8 thoughts on “Ask The Sietch – Easy Cheap Solar Heat”

  1. Radiant flooring has truly come a long way and must be experienced to be fully appreciated. Retrofitting an existing home can be tricky, and is often not very cost effective, but the application of radiant in new construction is huge. Don’t forget, you could be eliminating the purchase, installation, and maintenance of a potentially troublesome HVAC system. At least the heater part of the equation.

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  3. That was a great explaination. Do you know if today’s solar improvements add or detract to a properties value? Solar improvements from the 70 & 80s usually detract froom the value as people are wary about maintaining them.

  4. Kathy, most modern renewable energy systems add value to the home. The systems from 30 years ago are like any home system from 30 years ago, the technology was not nearly as good.

  5. Very interesting post and discussion. While our company ( is not involved with floor heating solutions, we are introducing unique passive solar heaters that are disguised as window blinds. The system was developed with the assistance of the University Of Minnesota/Duluth (those people know cold!). We will be ready to launch on Friday via our web site.

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