One of the major expenses faced by homeowners, especially in Ireland, is the cost of heating their houses. Anything you can do to help cut this cost is going to provide a major benefit to you.
Some homes are better designed for heat retention than others because they have effective central heating systems, but not everyone can afford a complete remodelling of their home, so usually we need to look at other methods for solving the problem.
Thermal exchange is always happening in nature because the laws of nature dictate that the perfect order for everything is homeostasis. This means whenever anything like pressure or heat is greater on one side of something than on the other, nature tries to find some way to equalise it. This is what you're fighting against.
Modern designs attempt to use a lot of glass in their construction, which saves on construction costs, but the trade-off is that windows are the biggest cause of coldness in your home after the sun goes down. However, they can also make your home unbearably hot during summer.
The first obvious solution to these problems, if you can afford it, is double-glazing. Ordinary windows suck heat energy out of your home because glass is an excellent thermal conductor. This means it transfers heat energy from your home to the colder air outside.
Air, on the other hand, conducts heat very poorly. When two panes of glass have a layer of air sandwiched between them, the transfer of heat energy from inside to outside is slowed down, making heat loss less rapid.
Adding thick curtains or drapes will also help, since these will create a barrier between the air in the room and the glass of the windows, again slowing down the rate at which the glass can remove heat.
Of course you should also ensure you haven't accidentally left any windows or doors open, because this will undermine your efforts by allowing cold air to come in from outside.
Radiant heaters include electric radiators and open fireplaces. You can improve their efficiency by installing tinfoil behind the heater. The tinfoil can be used to reflect heat energy back into the room which would have otherwise been absorbed into the wall and then transferred to the cold air outside.
Ordinary kitchen foil can do the job in a second, but with special reflective foil being cheap and readily available, it's definitely a better choice.
Older homes may have inadequate insulation installed, or even none at all. Walls that have cavities can have those cavities filled with foam or other insulating materials. This is not expensive and is very easy to arrange.
Thick insulation "batts" can also be installed in the ceiling space, and while they're more expensive than other insulation materials like fluff or sprayed foam, they're better quality and provide less of a home for rodents or other creatures.
Both types of insulation will help reduce the rate of heat transfer from inside to outside, and as a bonus will also help with keeping the house cool in summer.
Because heat rises, a substantial amount of the heat energy that isn't lost through the windows ends up getting lost through the ceiling. Good insulation more than pays for itself through the energy savings it provides, not to mention the greater comfort your family will enjoy.