Climate Control (heating and cooling)

Keeping your home at a comfortable level can be quite expensive in dollars, energy and pollution.

There are two major areas to look at for controlling the temperature of our house and immediate environment. the first of these could be called ‘active’, where there is a direct energy input such as a wood fire, electric heater or air conditioner. This is where one sees the costs of running the house increase with use.

To reduce the need for the active component of climate control and maximize its effectiveness, we look to the second division, the ‘passive’ part. Passive also means that you don’t need to do anything once things are set up. That means a saving in that other great resource – time.

Consider the following point before we go much further – the best insulator is motionless, still air. Keep that in mind, and you will find what follows to be quite easy.


To heat a room, we either allow the heat to enter (as in letting sunlight come in through a window) or trap the heat that is already in the room and prevent it leaving.

The easiest way to do this is simply to block off gaps that allow uncontrolled airflow. Gaps around and under doors or around window frames, open vents and fireplaces, even exhaust fans can let heat escape or cold enter in Winter and hot air to infiltrate in Summer.

Door seals

The quickest and easiest way to seal doors and windows is to use the foam door seal strips that go around the window or door frame and stop them from leaking. There are also the under door seals, or ‘weather strips’,that seal the gap under the door. They are also called ‘draught excluders’ and range from elaborate, hinged devices to the old fabric ‘snake’. Ultimately, they do the same job, they stop air from moving into or out of the house.

Sealing around the door of our laundry last year gave almost instant benefits with an average of a 2 degree rise in temperature in that room over Winter! Doing the same in the lounge the year before gave us a rise of 1 degree on average. That meant that we could lower the thermostat  for the same level of comfort (or take off one layer of extra clothing!).

In Summer, we noticed a reduction in warm air entering through the doorway too.


A lot of heat enters or leaves a room through the glass of the windows or gaps in the frames. We have sash windows, which are notorious for not fitting properly.

One quick and very cheap way to insulate windows is to use bubble wrap. It’s a cheap and easy to install insulator that can make a very big difference. Not only do you add a layer of plastic to the glass, but the little bubbles are little pockets of still air (remember, it’s the best insulator). You can use bubble wrap in Winter to keep the heat in or in Summer to keep it out,

One of the joys of using bubble wrap is that to install it, you only need to cut it to size, then wipe the window with plain water. Press the bubble wrap to the glass and hey presto! It sticks.

To stop airflow through the cracks where the windows meet, I just use plain old sticky tape. It’s cheap, and it works. Add another degree of temperature to that room!

By far the most effective way to stop heat and air loss to room is to have curtains. We made our own using a layer of quilt fabric and 100% block out fabric backing. It was a bit pricey, but I got the quilt fabric for free, so that made up for it cost of the block out. We didn’t buy the block out all at once, either. We did one room at a time, as finances permitted.

When fitting your curtains, be aware of something called ‘thermocycling’.

Thermocycling is when heated or cooled air flows past a window. For example, in winter, the warm air at the top of the room is cooled when it hits the cold glass, then falls as it is cooled, reaching the floor. This displaces air at that level. As this air is warmed, it rises, then hits the cold glass and falls. You get the picture…

So, how to stop thermocycling? It’s as easy as blocking off the top and bottom of the curtains. When fitting them, make sure they reach the floor. That stops the hot or cold air flowing at bottom.

For the top, install pelmets. They’re the boxes that you see, above some windows. We took a cheap shortcut and laid wide canvas strips along the top of the curtains where the pleats are. These we secured with safety pins. It’s cheap and it works.

So, door seals, floor length curtains and pelmets and bubble wrap. That’s a winning trifecta, that will allow you to use your heating appliances much less. That saves money, and reduces the amount of greenhouse gasses generated.

Roof and ceiling insulation.

That’s expensive, but well worth the investment. You can get by by using the commercial stuff and installing it yourself (a horrible, horrible job!) room by room. In our old house, we started with the main living room and main bedrooms – it’s your living space that you’re heating, and later, when finances permit, you can insulate other rooms.

Ceiling insulation works to make a barrier to heat whether it is coming in or out. It therefore works with other means of cooling. The direction of its effects change with seasons. In Winter, it is a barrier to heat getting out and in Summer, to heat coming in. In short, it keeps the heat where it is highest. You still need some way of venting or moving the heat build up that occurs inside in Summer though. That heat comes from bodies, cooking, showers…all sorts of things and is trapped there by the effectiveness of the insulation. If you can reduce the inside temperature at night in Summer, the insulation will keep inside at that temperature until other sources of heat let the temperature build up.

Cornices and skirting boards. 

These often move as the house shifts and can open up some quite large gaps. Ideally, seal them with caulk or silicon sealant or similar, but as a stop gap measure, push some fabric or paper into the hole to temporarily seal it.

Manhole cover.

The access cover to the roof cavity can be loose and poorly fitting. See if you can adjust it, or, as we did, put a sheet of cardboard or coir flute over it during the cold weather.

Exhaust fans. 

Bathroom and kitchen exhaust fans are wide open to the roof cavity, letting heat escape   continuously in Winter, even when not in use. In Summer, they can allow hot air into the house as strong breezes and wind causes the air in the roof cavity to move.You can reduce the heat loss from living spaces by closing the bathroom or kitchen door or there are caps with pivoting lids that are easy to install on top of the exhaust fan. These allow air to flow when the fan is on and settle back over the hole when it stops. You don’t need to go into the roof cavity to install these, just remove the exhaust fan and slide the two pieces through, then clip then together around the hole in the ceiling. Then you just return the fan.

Old exhaust fans can us a lot of power for the short time the’re in use. Those that I removed from here averaged 80W each! I replaced them with low energy fans from Arlec that draw, around 4W each. Their flow rate is lower than the old style fans but their power consumption means that you can have them on for longer and still use less power. They’ve become a big piece of our temperature control system. At night, when the outdoor temperature drops below the indoor temperature, we turn the kitchen, toilet and bathroom exhaust fans on and open windows. That moves hot air out of the house and draws cool air in from outside.

If you’re replacing exhaust fans with low energy models and adding draught stoppers, make sure the draught stopper is light enough to be opened by the pressure from the fan. Some models are a bit too stiff at the opening and won’t open.

In many cases, you won’t need an electrician to install exhaust fans. Many houses have a plug in the roof cavity where you can unplug the old fan and plug the new one in.

Air-conditioner vents.  

Some of these close, other varieties are purely aesthetic. In theory, the air-conditioner is sealed and the conduit is air tight and insulated. This may not be the case with older units which will allow air to flow all the time. Either invest in closing covers or use cardboard to cover them. Some folks take them down and put newspaper or magazines inside to do the same job. We used coir flute sticky taped across the hole for a couple of years but last Winter, we had lots of scrap bubble wrap left over and put large loose wads of this into the vents to stop the draught.

Wall vents.    Ours’ is an older, double brick home with 2 wall vents in each room on both the inside and outside bricks. This is  to prevent dampness from building up in the wall cavity, but is a case of overkill. We close off one of each of the inside vents in each room with a square of cardboard and Blu Tack. This reduces heat loss in Winter because the vents are near the ceiling, where the hot air goes, but still allows some flow throughout the cavity. We have whirly birds on the roof so they draw air through the wall cavities into the roof space, so we don’t need to worry about negating the effects of the wall vents by blocking them up.

Power points.  

This is  something that I’ve only recently found out about. Some power point plates allow air to flow through the holes where the plugs go. As I found from experience, the draught from these can be quite strong. We now keep them sealed with those little plastic plugs that you can buy to keep kids from poking things in to the power point. Alternatively you  can just leave things plugged in (but turned off when not in use) or cover the plug holes with sticky tape.

How well does it work?

We’ve done all of the above and, on average have reduced our winter heating from 3200W (two 1000W and one 1200W heater) down to one 1000W heater and a second that is set down to 800W. That’s a saving of 3200 – 1800 = 1400W per hour!

At about 30c / kWh, that’s 42c an hour saved, not to mention about 800g of greenhouse gas emissions that we’re not adding to the atmosphere each hour

The average indoor overnight temperature drops to a minimum of 11-12 degrees Centigrade, whereas before, when the heaters were off, it would drop to 8 C. That means that the place more comfortable at all times.

As the house is quite long, we initially had a temperature difference between the lounge and the bedroom of 4 C. Now it’s only 1 C. That means that we don’t need a heater in the master bedroom at all!

That’s a massive saving over winter!


We’re still calculating our savings for Summer. Power use has been going down and the big cooling appliances are being used less but the temperature is increasing every year. The garden is a big part of being comfortable in Summer and that’s only just reaching its maximum.

Last year (2018) for instance, we had 70% shade cloth all around the house. This year (2019), though we’re only a few weeks into the heat I’ve replaced some of that cloth with 90% and added additional shade sails underneath the old shade cloth at the back, where things could really cook.

At the front, so that we still get a pleasant amount of light, I’ve left the top cloths at 70% and added layers of white 50% block in those gaps where the afternoon sun still gets through enough to heat the place. The white still gives a certain amount of brightness that is quite pleasant

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