Written for Malachain: the essentials, without the noise.
A heat pump works like a refrigerator in reverse. It collects heat from the outside air, the ground or water and moves it indoors using a refrigerant cycle powered by electricity. Because it moves heat rather than generating it by burning fuel, a well-installed system can deliver several units of heat for every unit of electricity it uses, even in cold weather.
Heat pumps run best at lower temperatures for longer periods, so good insulation and correctly sized radiators or underfloor heating make a large difference. Before deciding, ask an accredited installer for a heat loss survey of the whole house rather than a quick estimate. Check which local grants or incentives apply, since these can change the cost considerably.
There is more to learn on this subject, and the linked website goes into greater depth. Treat this article as an introduction rather than the final word, and check any important decision against up-to-date, reliable sources before relying on it.
If you try any of these ideas, start small and adjust them to your own situation. What works for one person will not suit everyone, and it is fine to keep only the parts that help. Writing down what you changed, and what happened, makes it much easier to see after a few weeks whether the effort was worthwhile.
The most useful step is usually the first one. Pick a single suggestion, try it for a couple of weeks, and then decide whether it is worth keeping. Small, steady improvements last longer than ambitious plans that are hard to maintain once everyday life gets busy again.