After housing, car and food, utilities are quite likely to be one of the biggest budget positions in an average household.
Actually, it is amazing how much some people spend on heating, electricity and water, and how they even think this is normal and inevitable. From my surrounding I know people who spend as much as 130 EUR on electricity and 105 EUR for gas per month for ONE person. And in Money Mustaches Blog, there was once a guy that spent more than 300 USD (=200 EUR) per month on electricity for a family of three, which corresponds to even higher figures in Germany, where the price of electricity is at least twice as high as in the US.
So what do these people to with all that electrical and heating power? Are they trying to add to global warming by heating with the windows open, because they perceive their area of living as too cold? Are they running 3 mega-huge flat-screen TVs 24/7? Is there an extended demand of ice cubes to produce christmas ice sculptures? Are they running a secret laundry service in their basements?
Or, god forbid, are they just wasting energy, because they never put a single thought into efficient energy usage?
Let’s start with understand efficient heating first.
(Electricity use will follow in a separate post.)
To do this it is helpful to learn a bit about the physics of heating to understand saving potentials:
Warmth actually can transmit in three ways:
Warmth is transferred by direct contact of two objects. E.g. if you touch a hot plate or if air in your room is cooled by touching the cold glass of the window
Warmth is carried away by a fluid element. E.g. wind is carrying away the protecting warm air around your body. Or the cool air next to the window sinks to the floor as it is heavier than the warm air inside the room.
Warmth is transmitted from a hot object via radiation. E.g. the sun feels warm in the face even in winter, or the fire in a hot stove warms you if you stand in front of it.
Another important thing to know is the energy storage capacity of different materials:
- Air has a low storage capacity (it is not dense nor heavy). This is why you can easily stand 90 degree Celsius hot air, e.g. in a Sauna.
- Water has a much higher storage capacity (ca. 800 times air, given same volume). This is why you cannot stand 90 degree hot water.
- Brick, Metal etc. has an even higher storage capacity.
Knowing this, it’s easy to understand how heat is carried away from where it should be, e.g. in your house.
Now you can think about reducing the loss of energy by curbing or improving each of the energy transmission effect as necessary.
Some ideas are:
- Conduction has to be minimized.
- This can be done by insulating your house (very important!), by closing the blinds in the night, by wearing an extra pullover, by having a carpet under your feet, using a blanket.
- Convection has to be minimized if it concerns cold air.
- If there is a lot of convection in the room, cold air will spread and there will be an uncomfortable draft.
- A draft will require 3-4 degrees C higher temperature to still feel comfortable! And if some air stays where it is, it is acting as insulation (this is why styofoam works).
- Stopping convection is thus important and can be done by putting a barrier between cold and warm parts of a fluid (mostly the air), e.g. by having a curtain in front of the window.
- Closing doors in the house is important!. And of course insulating any gaps in windows, under doors etc.
- Even growing plants like ivy on your outer walls will help stopping convection of cold air towards your outer wall. This can save up to 10% of energy. Or you use a rough outer surface of the house as it is done in modern homes. The little creeks there will keep air from convection on a microscopic level.
- Convection of warm air is desired.
- Thus your radiators should be free, no furniture in front of the etc. The warmth shall circulate into the room, otherwise it will just vanish into the wall behind the radiator and to the outside. Same holds for an oven.
- An open fireplace is very inefficient. Convection will blow hot air right through the chimney. A metal wood burner (“Schwedenofen”) or a “Kachelofen” is much better, the hot air is slowed down there and will pass its energy to the metal and thus to your room, before leaving to the chimney.
- Radiation is often underestimated or not understood. Radiation in a room means that apart from warm air around you, you will pick up energy coming directly from radiating warm objects (like an oven, the sun, or even from a wall). If an object is cold it will radiate less and people perceive this as cold radiation (whereas it actually is only a lack in radiation, as there is no such thing as cold radiation). An extreme case is e.g. after sun settles on a crisp winter evening in the mountains – drop in radiation from the surrounding can give you an extreme feeling of coldness there. However, for heating purpose, radiation is very important:
- If radiation is high, you will feel quite warm even at lower air temperatures. High radiation can be reached by:
- Sun falling in through a window. The radiation from the sun (not only the light but all of its spectrum) will be reflected around the room and will make you feel comfortable. Thus choosing a house with big (and well insulated) windows towards south-west is VERY helpful to curb heating costs. The sun will heat your home PLUS make you feel more comfortable by the radiation it provides.
- A metal wood burner or a “Kachelofen”. The very high temperature of this type of oven provides radiation (infra-red radiation in that case) that is reflected throughout the room. Apart from the direct heating effect, this radiation will increase you level of comfort even at low air temperatures. Thus an oven is a good investment. Another plus is that you can make it comfortable in short time, thus you don’t have to heat this room when you are not there.
- Floor heating. Floor heating provides a lot of positive radiation , but I am no expert here.
- Low radiation (“cold” radiation) is not desired. Unfortunately it will come from any badly insulated and thus cold object, like a single-glas window (replace this immediately!) or from a badly insulated outer wall. The effect there is opposite to sun or oven: The bad insulation not only wastes energy to the outside, but it also makes you feel more uncomfortable, even at high air temperatures.
- High energy storage capacity of walls means: If you are ventilating fresh air into your home, do it by opening all windows and doors of your home at once for 5-10 minutes once a day or so (turn heater off). This way, all the air inside will be replaced. But as 95% of the energy in your house is stored in the wall, not much energy will be lost. It will feel quite cold for another 10 minutes inside the room, but then the air gets warmed up by the walls. This way you get a lot of fresh air in by loosing little energy.
- Venting by tilting the windows is much worse, as it constantly drains energy from the room without a full exchange of used air. And you virtually heat energy out of the window.
- In the night lower heating by using a heating computer.
- Use modern burners in your house. As insulation of walls, roof and new windows, this is in most cases an excellent investment that will give you easily 5-10% return p.a. Consequently don’t look on this as one off costs, but as an investment.
- If you rent, you should negotiate with your landlord and offer him to pay a slightly higher rent if he does the investment. This is a clear win-win situation, especially if energy-saving investments are tax-deductible as in Germany.
- Definitly change to a cheap supplier of gas. This can easily safe 200-400 EUR p.a. in Germany. But be care-full not to pre-pay nor bind into too long contracts.
- Ask around at your neighbors to get some wood from their garden works for your burner if you have one.
- Arrange with local forest owners for pick up of dead wood allowance.
Following this basic steps, most households will have significant saving potential to their heating costs.
You can easily save a couple of hundred bucks each year here and save the environment as a plus!
At Woodpeckers, our current heating energy consumption is as follows:
- 10.500 kWh of gas per year (last five years avarage) plus around two cubic meter of wood for the metal wood burner. This is for a 150 sqm home, built early 90s, 4 persons, heating done with gas, two days homeoffice of Mr. Woodpecker as well as Mrs. Woodpecker.
- Gas provided by Maingau Energy. Switch to them saved around 200 EUR p.a. in Woodpeckers case.