Does your boiler SPEND TOO MUCH?

FAST or SLOW Heating?

There is a general tendency to have very powerful boiler and very hot water heating circuit. Just to stop after a while and then cool the house. ¿Run like a HARE or go quiet as a TURTLE?

Let’s imagine you have a 50 kW oil boiler. You run it only few hours a day because you do not want to spend that much oil, being cold the remaining hours of the day.

When the installer advised you a good power boiler, may have been for the following reasons:

- He looked at colder temperatures in the area in recent years. He proposed a big enough boiler to be sure that in those cool days you should be warm (and don’t claim about an insufficient boiler).

- He made the assumption, probably true, that the house had a poor thermal insulating.

- He advised a powerful boiler which could heat the house very quickly when cold.

With these three premises, the supplier of the boiler “HARE” made sure you were warm when you wanted (at least several hours) and not call him to claim more power. But who pays for the fuel? You or the installer?

How to be warm at home with a low-power boiler?

First you have to change to a new philosophy of the boiler “TURTLE”: slowly and steadily. To do this my advice is:

- Maximum thermal insulate of walls, ceilings and windows. It is the most efficient and economic investment in order to have a small boiler and also not be cold.

- Working with VERY LOW water temperatures, even with conventional radiators. If you have to build the house again, it is better to put underfloor heating, but if you already have radiators, use them. Instead of heating water to about 70ºC (F 150), make a single test just with  40ºC (F 104). Or try the just No. 1 or 2 in your control water temperature. It is a topic of patience, inertia and total energy emitted at daily basis.

- Do not stop the boiler all day and night, but with different setpoint temperatures in housing, for instance 20°C (F 68)day and 16ºC (F 61)at night. It is very important not to turn off the boiler at night and let cool too much at night, since a small boiler should take too long to heat up again.

- The boiler must be modulated (either gas, pellets, oil, etc.) to be able to work only 30% or less of its rated power. For example, a pellet biomass boiler of 12 kW could work only to 3 kW for not stopping the boiler and maintain a certain temperature in the water circuit.

Heating Hare or Turtle?

Following the fable, the heating “rabbit” accelerates with great energy and suddenly stops, accelerates and stops again. A great waste of energy that is paid every month with the bill. And going cold in a few hours.

The heating “turtle” has little power, runs slowly, at low temperature and does not stop. Maintain a nearly constant velocity implies a high energy efficiency. What you will notice on your bill and not go cold.

A lot remains to be said about the thermal inertia in the rural heating. What do you think of this idea? Thank you for your comments and experiences.