Insulation: First the body, then the home (2011)

> It takes a lot of energy to raise the temperature of a house - more than to maintain a given temperature

is this true? the house is constantly bleeding off its heat at a rate proportional to the temperature difference between interior and exterior. it should always cost more energy to maintain the higher temperature gradient than to just let the heat bleed off (which it was always going to do) and add in more heat once the building is occupied.

I'm German, studied in Auckland (NZ), worked in Sydney and Melbourne and am now living in Sweden. The coldest I've ever felt is Auckland and Sydney (probably Sydney slightly colder). Sydney houses are so poorly insulated, there's cm-wide gaps under some doors and windows and the only heaters are typically a small plugin resistive heater. Auckland was typically a bit better, except that the heaters were indoor gas heaters with a LPG bottle (welcome to dampness and condensation on all windows).

During the day in Sydney winter it is often 18-22 degrees, so you can walk around in t-shirt quite comfortably, but as soon as the sun goes down it drops down to 8-12 and it's as cold inside as outside. Try to work on a computer when it's 12 degrees in your room (or maybe 15 if you have your electric heater on full blast).

Melbourne gets much colder and insulation is only marginally better. However, apartments/houses typically have some sort of proper heating (heat-pump or centralised gas heater). You still largely heat the outside though (one of our houses was so badly insulated, that when it was windstill the house could be easily heated to ~20 deg even with ~1 deg outside, when windy that indoor temperature dropped to >10.

Now in Sweden, I can easily sit in t-shirt and be comfortable. In fact my office can be heated just using my moderate desktop PC (~450 W power supply), because you don't loose the heat to the outside immediately.

When I moved to the UK and I was looking for a property to rent I was surprised to read advertisements bragging about "double glazing". I don't really remember seeing single glazing in my home country (even pre-second-word-war had double, just not two pieces of glass in a single window frame, but two separately openable single glazed windows). But it doesn't get that cold (outside) in winter in the UK, while the strongest winter i remember was getting down to -30 degrees celsius. However houses are definitely cooler inside in winter in the UK.

Nowadays there are increased requirements for thermal insulation in new houses and many new buildings where I come from have triple glazed windows, some people get recuperation (warm air having house warms up newly coming air) and some even heat pumps (winters got milder recently, so even air source heat pumps are sufficient most of the years)

Talking about Canada, when I was an exchange student in Halifax, New Scotia, one day when the snow fell (not even a particularly big amount in my opinion) the uni cancelled the classes; we were some of not many people who arrived to the uni building so we went sledging on a small hill nearby. It was the only time in my life that school/uni was cancelled due to weather! So Halifax didn't live up to the stereotype and my expectations about Canada, but maybe it's because it's not really a hardcore part of the country :)

Yes, because when the inside of the house is close to outside temperature the temperature difference is lower (obvious). Heat loss depends on temperature differential so there will be less energy lose.

The real question you should ask isn't is it true - it is. The real question is it significant enough to worry about. If you are going to be gone for several days it is.

If you are only talking about a part of a day though things are different, and get complex.

If you heat with electric (including heat pumps!), keeping the house a consistent temperature makes you use an even amount of heat all day, and so your house can be better supplied by renewable energy. If many people turn the heat up when (or just before) they get home at 5pm - the renewable power available isn't enough and the power company will have to turn on fossil fuel plants to make up the difference. Thus you might use more energy but use a better type of energy by keeping the house warm.

For many houses solar heating (from windows) is nearly enough to keep the house warm all day even on the coldest days, so it doesn't matter as the heating system isn't working anyway.

Note that the previous two paragraphs contradict each other. I don't know how to work that out (for cooling it is a big deal), so you will need to ask questions - be prepared for different answers at different times.

If your house is well insulated you shouldn't see much a change in temperature indoors, and as such there is only a tiny amount of energy save with setbacks. So why not just enjoy a comfortable temperature for the rare exceptions to your schedule? If your house is not well insulated, fixing that should be your priority.

There are probably other factors I can't think of.

I think you forget how people make choices. One of the big issues is that if people are given the choice between an extra 3rd or 4th bathroom (that they use twice a year) and good insulation, most people will choose the 4th bathroom. That is because the bathrooms are considered status symbols while insulation is not. Now the rational thing to do when building a house, is to choose the most energy efficient solution over any other options (e.g. a better kitchen), because more energy efficiency will allow you to afford the other upgrades sooner. However, few people make their choices like that.