Thermal Collector System

First question, I always get when I bring the conversation round to the collector system is:

"Is it economical???"

The funny thing about this is, that nobody asks us the same question, if we buy a new car. The same applies for a PC, a notebook, a sitting area, and so on.

But in case of the collector system the answer is: "Yes!" But more on that later...

We have always had an eye on a thermal collector system, but in those days, when we bought our new house, we stopped that plan for cost reasons. And that decision was good, because our first plan was made just for preparing warm water. That would have hardly been worth it - for neither the environment nor for us. Because the energy portion which is used to prepare warm water) in relation to the total heating energy demand (warm water + heating) is about 13% - and maybe you can cover 60% of these 13% by the sun. In total this is 8% of the total energy demand for heating and warm water. That is better than nothing, but nonetheless conceivable little. (see right picture)

If you only have an eye on preparing warm water by the sun, then you will nibble at the little piece. You should try to bite off a proper piece of the big cake. What size this can be, I try to demonstrate here. But at first: This is not tranferable to all other environments one-to-one. It depends on structural conditions (size, living space, insulation), the alignment of the building, the habits of the residents, the old installation and so on.

So: if you put expensive technology on your roof and into your boiler room, it should be well worth the effort, by trying to get rid of most of the remaining 92% heating energy and incidentally to warm up the water (and not the other way). There is only little difference in the wage costs whether the plumber installs a storage of 400 liter or a storage of 1000 liter.  Storage costs decrease in relation to increasing size of the storage and every additional square meter of collector area does not count much to the total costs, because subsidies are calculated on square meters in Germany. If you have choosen a small solution first, then

• the money is spent,
• the space on the roof is wasted,
• the space in the boiler room is wasted,
• ...for the next years

Now the sceptic says: "The dilemma is, that in the winter the sun isn't shining very much and in the summer you don't need the surplus of energy." But both no problem.

• The biggest benefit is obtained in the transitional period (March, April, May, September, October, November). Then the sun's power is already or still sufficient and there is enough demand for energy depending of the insulation of the building.
• The collector system adds some energy even on sunny winter days. It is not much, but it counts. But you should not overrate this energy portion in December and January.
• The heating can stay off and need not to run uneconomically for preparing warm water.

Therefore the reasons for a change in the system are obvious...