I had posted a question a few days back (in the older chat lounge) about replacing my radiant heating system with something else. I looked into the suggestions I got regarding the Unico system. It is a good option, but unfortunately I found that its a fairly (read as quite) expensive one because it requires reroofing too (in my case, the roof is fairly new and doesn't yet need replacement). So I searched some more (hoping against hope :) ) that I'd find another solution. I came across something called a "ductless" system (aka "ductless split system"). I'm going to try to find out more information on this (haven't found out the cost yet!), but from what I've seen so far, it seems like a cheaper alternative. The question is, is it a worthwhile one. Does anybody have any experience with these systems?
I have not installed a split ductless, but did investigate them thoroughly. They *may* be an answer if you are just looking to condition one or two rooms. If we are talking about whole-house conditioning, then split ductless is not the answer.
Not having seen your prior post, I don't know if your old radiant system is dead, you don't like it, or you want to put in air conditioning. I'm going to assume it is dead beyond repair, and you don't want to pour a new floor to establish a new hydronic system.
If that's the case, and you just need heat (not cooling), then the other thing I would suggest is to investigate electric in-floor and under-floor radiant systems. These are easily retrofitted, and depending on the manufacturer can be placed under carpet, tiles, hardwood, etc., or even imbedded in a new skimcoat (1/4 inch). The benefits are that they do not change to aesthetics of your house at all, and you can create total zone control of the heat. The disadvantages are that you will likely need (1) to replace existing floor coverings (2) an electrician to put in some new circuits to support the load, and (3) the operating costs could be more than with the hydronic (could be less, depending on how you use it).
Hope that helps.
Thanks for your reply!
Your suggestion was quite useful. I'm definitely going to pursue this to see if it will work for me. I've been reading about it on the net, but there are a couple of questions that can be answered only by someone who uses it. So I would really appreciate your input.
1) Do you have this installed at your place? If so, are the usage costs reasonable? I'm worried that given the sometimes crazy electricity prices in CA, this can cost a lot. (The house is about 1200 sq ft, but from what I understand, a chunk of it will not need to be heated by this).
2) Do you know if this can be used as the primary (only) heating system? I've seen a lot of references to this being used as an auxilliary heating system.
Check out this link:
For someone who has already installed Flextherm. He seems pretty open to questions, so he can probably give you an idea about operating costs.
I have been investigating the electric radiant floor heating as an option for whole house heating.
Here are some things Ihave been made aware of.
California Title 24 regulates the energy efficiency standards of construction. :(
Of course the goal is to reduce the total electric power demand of California. see http://www.energy.ca.gov/title24/standards/index.html for the details.
One thing you will run into is that the electric radiant heat is not usually permitted as a primary heat source. It can be used as a secondary heat system, such as warming small spaces. WHole house heat can be electric radiant as long as it is not the sole source of heat. Believe it or not wood burning stoves and heat circulating fireplaces may qualify as primary heat. :)
Wood floors do have a higher R value than stone, concrete or ceramic tiles. Especially you should take care to install the wood directly against the heat element if the element is not embedded in a concrete layer. Any air gap will reduce the transfer of heat to the wood and then to your feet.
The last post to this thread was in 2003 so I wonder if you went ahead with the electric radiant heat.
I have a samsung ductless mini-split system and I love it. But we got it for AC, not for heat, though it does both. It is a great solution to the Eichler AC dilemma, but as others have said, I am not sure that it would be the best for a whole house heating system--and it is not cheap. We did 2 rooms (which virtually cools 50-60% of the house), and it was over $6K.
For another alternative to the existing radiant system, take a look at StepWarmfloor. There is an article about it in the Winter 2004 newsletter, so you may want to order a copy. Even though this system is low voltage and much more energy efficient than many of the alternatives, it does not conform with Title24, which probably says more about the regulatory process (often makes no sense and is very inflexible, taking years to incorporate the latest in technology improvements) than about the product itself. Nevertheless, it is being distributed throughout the US.
Franz Rogmans, a supporter of this site, installs them. Also, Henry Calvert, another supporter and GC has installed one is his own home, I believe.
Anyway, just some information that I hope you find helpful.
Have you considered hydronic baseboard? You may be able to even use your existing boiler. It involves over roof piping but doesn't require a new roof like the unico. It doesn't require new floor coverings either and works off natural radiation just like the floor did (no dust).
I did alot of research on the warm floor option and determined that it's a terrible idea for an eichler because is just doesn't have the output to meet the heat loss of the house. We have way too much heat loss in our houses for forced air or low mass warm floor systems... Even with a foam roof and sheetrock. Electric heat would cost a fortune.
We actually have hydronic baseboards and like them very much. While the existing radiant system tested as operable on inspection, the previous homeowner had baseboards installed in order to save $$ on the heating bills. She used the existing boiler and had the baseboards configured in four zones: kitchen/bonus room; LR/DR; MBR; back hallway and bedrooms. It is quiet and clean, just like the radiant systems are. I cannot speak to cost, but from what I have heard anectodally, they are not cheap, but then nothing is in an Eichler. Their biggest disadvantage would be appearance and the fact that you cannot place furniture flush against any wall that has baseboards on it -- however they are not on every wall -- just one or two walls per room.
I am surprised that you concluded that WarmFloor would not provide adequate heat output, given the fact that it was developed in Sweden and has been used there for years. I believe Swedish winters are a bit cooler than ours. I assume you looked at the data from the "test house" they did in Sweden, correct? OTOH, I have heard from the owners of the company, that they do feel different that traditional radiant systems, and that rather than feeling warm, they feel "not cold." This could be an issue for those wanting their tile floors to feel toasty warm in the winter.
Although the climate in Sweden is more extreme than ours, the test house is not comparable to an eichler in any way. The temperature of the climate does not effect the ability to heat a stucture. The insulation of the stucture is what can make or brake the ability to keep it warm. The test house in sweden was not a slab on grade house like our eichlers and had very good insulation values on every side. Unfortunately an average eichler by original design (no foam roofs or in wall insulation or dual pane windows) has 45-50 BTU per square foot of heat loss. I had a terrible time getting a BTU number from the manufacturer but finally talked to the engineer who told me the step had a maximum output of 24 BTU per square foot. I'm an engineer an I love to know how things work. I just dont think it has the output to offset the heat loss of the common eichler. He also said that in the house in sweden the equivalant of one kilowatt hour equals $.07 . Ours is twice that.
On a side note... This is a great forum. I'm glad we have the ability to chat so openly with other eichler owners about this stuff.