constanze, what I don’t understand is why, since HVAC decisions are so dependent on ones local climate, as well as on the relative costs and availability of fuel, that you’d feel qualified to give advice on the subject half a world away.
constanze - I am a big advocate of Solar Thermal, and I will agree with you that it can be very cost-effective. However, it is not really very easy to retrofit houses with this technology. The best Solar thermal systems are passive - they use the house itself as a collector. Trying to add this capability to an existing house could be expensive, and very ugly. I think that some of the other posters saw the “solar” in your post and thought “PV,” which is probably the worst possible way to heat a house. In this instance, the OP is probably better off just adding supplemental heat, rather than trying an entire remodel.
I still don’t know how much a solar system in the US costs, so I don’t know how much more expensive it is compared to one in Germany. I don’t know the amount of subsidies the US govt. currently offers for solar vs. compared to Germany. But if you claim that solar in the US is too expensive, and doesn’t last long enough to recover the cost, so only people with a large cheque - I assume you mean rich, or at least upper-middle class; over here, people with at least 6 000 Euros gross monthly income, I’d guess (please correct me if you mean different) - can buy it.
I also don’t know if the average (which is of course difficult, given how wildly the standard, size and location of houses varies anywhere) houseowner in the US needs a larger solar area than in Germany because the insulation, and therefore the energy needed per square meter/ foot, is larger.
I do know that back in the 90s, the people who put up solar here in Germany were upper-middle class people, who used the special govt. loans, and tax write-offs, and PV payback, to help. They had that enviromental conscience very strongly, and long-term, (that is, 15-20 years) planning.
In the last 5 years, however, people from normal middle class (say, around 3 500 Euros gross income a month) have changed to solar because of increasing oil and gas prices. Now, generally oil and gas are said to be cheaper in the US, though I don’t know how much the difference is currently.
Now, since you talk about writing a large check, maybe you do things differently in the US. Maybe homeowners look at their savings account and say “I only have 2 K, so I can only buy a system that costs that much” I don’t know.
Here, people look at how much they spend on oil/gas per month already, multiply by 12 for one year, multiply by 10 or 15 years, and consider investing that. Then, when switching to solar, the homeowner goes around different banks comparing loans and gets a good one, and pays off the loan from the money otherwise spent on heating anyway. There are additional tax-write offs, and loans with a bit lower rate, and a grant at the start, as subsidies from the govt., that enable people with lower income to switch. If you use a model like this, you could make a larger investment than only with what you have saved up.
I was confused by this remark, so I did some Googling and discovered a difference in terminology.
So, when I say “boiler” I am referring to what you would call a “furnace”.
Oh, I see. Thanks.
In the USA, furnaces into the 1950s were made with plate steel heat exchangers. They rarely fail. They get replaced because they are loud (compared to new furnaces) and inefficient.
Since the 1960s they’ve been made of sheet metal and will generally last 25 years, give or take. My experience is that they are getting better and better with comfort and efficiency and other features, but not as well built.
A furnace installed in 2009 would have a life span of 20-25 years in my estimation. (and most have 20-25 year warranties)
Oh, so you mean the annual/ regular inspection by the water expert, not a weekly/ monthly maintenance by the homeowner. I misunderstood what you were snarking about.
Well, you could fight ignorance by simply explaining things, not only for me, but for the lurkers and other posters, too. Unless you think I’m the only ignorant here not to know how to deal with a water boiler (which I’m not licensed to do, as I’m not a qualified expert).
Or you can continue snarking/ debating.
Well, since you didn’t elaborate on what you meant initially, I guessed that you meant regular small-scale maintenance. I haven’t had opportunity yet to talk with my local janitor as example of what he does in regards to the boilers, and what he leaves to the licensed experts, who do regular inspections and some form of maintenance with it.
Since I don’t do this for a living, and am not present during their inspections, I don’t know the detailed scope of what they do.
If I were a small homeowner, I would call the expert for inspection at the prescribed / recommended intervals, and not need to know details of maintaining it, either. So since the question was about how difficult a closed-cycle water-based radiator system would be for the normal home-owner to maintain, I don’t understand why my answer that I don’t know about these systems is dumb, if your own admission is that normal people like janitors don’t do it.
Well, at least my friend was more civil. I asked my friend for confirmation because he has experience both as small home owner and from work with boiler systems; and now is not the time I can talk to the real experts who work with water for a living.
And yes, I will take my friends word over your claim.
I don’t know what you mean with potshots - I have stated outright that I don’t know details of how things are done in the US. Is that not allowed?
But since raindog is expert on everything, and I know nothing, I don’t know what more I can contribute. I also don’t want to discuss my suggestions - This is my last day off work, so I don’t have much time to research things which don’t seem to apply in your country anyway.
I do have a list of questions that are usually asked by energy consultants here - you don’t have to answer them publically, rather, they show the many directions in which a good consultation goes.
How many square feet does your house have?
Do you know the insulation factor of your walls?
Have you had an infrared spectral image taking of your house identifying weak spots? (A good contractor should offer to do this for a small fee; maybe an environment group will offer to do it. They also usually have consultants.)
Orientation and location: where do the windows of your house face? Two big windows south and no windows in the north side is good for warmth.
Where is it located - on a hilltop with howling winds? Deep in the forest in the shade? Deep in a hollow, where cold air pools? Near a rock face, which reflects sunshine? Alone or in a village?
Windows: Do you have double-glaze? (I’ve heard anecdotally that it’s difficult/impossible to buy double-glaze windows in the US, but I’m doubtful to believe this).
I would choose a company with trained experts who have a lot of previous successful projects to do the insulating for me, even if it’s more expensive than buying stryofoam panels and having untrained day laborers nail them to the wall, because the tricky part are the cold gaps wherever two materials meet, e.g. roof/walls and walls/windows.
Roof and basement need special insulation, too.
Before you decide on insulation, you have to choose the materials. They should be in the right order, so that the dew point of the water vapor leaving your house is on the outside, where it can evaporate, and not inside, where it could cause mold.
Important in this regard, as well as with heating system itself, is the usage pattern and the type of people who live there:
Stay at home the whole day, or work outside?
Cook every day in the kitchen (= generates heat and vapor) or rarely?
Shower every day (= generates vapor) or weekly?
thin and freeze easily, or sport people with high metabolism?
Of course, usage patterns can change - staying at home/ going to work esp. - but it’s helpful to know how much water vapor your windproof sheeting has to handle.
If both of you suffer easily from cold feet, because of low blood pressure, a floor heating ( a thin heating coil laid beneath a wooden floor - doesn’t work with all kinds of flooring) can add a lot of comfort and lower the general room temp.
If you prefer to keep the air-based heating system, maybe you could convert to a closed air system with heat exchanger in the basement, that takes the warmth from the used air before venting it outside, and using it to warm up the new air from outside. Some house builders here offer it, though I’m skeptical about stagnant corners that the air flow doesn’t reach. The best would be to ask to visit some houses with those systems installed, talk to the owners and see how you like the air quality.
I don’t know how much energy you currently use, or what figures your house has, but for an old house, up to 70% saving with proper full insulation (roof, walls, windows) is possible. So for every 10 dollars you spend on heating today, you would save 7 $, which is what I would use to pay off the loan to finance the big cheque you have to write for the company.
I’m not talking about sub parts, but different trades. But it’s difficult to accurately assess this without having a good description of the job for comparision, because as non-expert I don’t have the technical english vocabulary.
No comment. If you don’t understand the value of thorough training and education, then probably it’s one of those differences in attitude between cultures.
Forgive me for throwing out suggestions since the OP asked for general instead of specific advice. Of course specific advice depends on a lot of individual variables. But since the OP didn’t start out with a detailed list of all those variables for her house (which would of course be inadvisable on a public message board), I assumed that she was looking for suggestions to know in which directions to look locally. I also assume that the OP will collect the suggestions and also probably data elsewhere, and then look around at energy consultants locally, and companies that do the necessary work, and these local people she talks in person with will get the details to crunch the numbers and give cost estimates. If that assumption was wrong and the OP wants concrete figures and not general points, then I will leave this thread.
Forgive me also if it was a mistake to assume that a different or additional perspective would be welcome or helpful or at least interesting.
This was initially confusing for me, for I see lots of old houses retrofitted with the rising oil/gas costs (my brother-in-law recently converted, and he didn’t do it for green conscience, only for cost and because it’s quicker than using the wood tile oven they also have), but maybe it’s because of the different technology of heating itself - air flow vs. water radiators? Because with the water based system, you just put the thermic panels on the roof, hook up the pipes and the heat storage tank and are done, and depending on the roof height and angle, you may not even see the panels from the road.
Though some house companies offer new low-energy houses with closed air-flow systems and heat exchange, and I thought they also could use solar (but I don’t have access to the brochures right now).
But the OP said she’s already using electricity to heat, so in the case of PV, the panels would simply be hooked up to the existing system. Or is the life-span of PV panels in the US as low as the anti-solar people always claim (that they last less than 20 years?) To use the first source available, wikipedia says
for end users of PV array at home which can use the guaranteed payback of the german-style subsidies, depending on the choosen technology, finance costs (= interest etc.), the margin of the big traders and the pay for the installation craftsmen, currently return of investement between 8 to 15 years, depending on start of the array. In countries without subsidies the same array (assuming similiar climate) would only return the investment after 10 to 30 years. Despite this, PV arrays can often be run more economically in countries without subsidies because of the more suitable climate (for example, in countries along the equator), because the amount of sunlight per area is multiple times higher (Translation by me)
Now, the OP is not at the Equator. But she is further south than Bavaria.
and
Since PV Arrays have hardly any mechanic attrition, it is hoped that they will regularly last much longer and remain fully functional for longer than the projected recovery period (in this table, 20 years)