Heating your home - heater, heat pump or boiler?

A radiator under a window with open curtains and two jumpers

What exactly are the differences between storage heaters, immersion heaters and boilers? Which are more energy efficient? If you’re considering changing your heating system, which one should you go for? Which product is better for space heating and/or water heating? Let’s consider what you need to know before looking, and review the different hot water and heating solutions available.


Before Looking...

Some key issues we advise you to keep in mind when researching updating or changing your home heating system are:

  • Cost
  • Fuel accessibility
  • Your individual situation
  • How heat-efficient your house is

Cost will obviously be an important deciding factor, depending on your personal situation. Not only the initial cost, but also maintenance and upgrade costs. Is it financially viable for you to do a complete overhaul of your heating system, or can smaller upgrades be made?

Fuel accessibility is another important factor. Gas is currently much cheaper than electricity when it comes to heating your house, so if you’re not connected to the gas network, you’ll need to weigh up the cost of connection against using electricity, installing an LPG or oil tank, or alternative heating resources such as solar, or heat pumps.

Your individual situation- how many people live in your house and how big is it? There is a sizeable difference in the energy requirements of a five-bedroom house occupied by five people, and a five-bedroom house occupied by one person. To this end you’ll need to consider which spaces need to be heated constantly, and which can do with being rarely heated (spare bedrooms for example). Bigger is not always better when it comes to capacity, as oversized solutions will contribute to energy wastage. Will you need to be able to turn on more than one tap or shower at the same time (think about the morning rush to get ready for work and school), as this could impact the hot water aspect of your heating solution.

How energy efficient your house is will also heavily impact your choice of heating system. The insulation and airtightness of any home dictates how efficient a heating system will be, and how much heating effort will be needed. If your house is well-insulated and airtight, you won’t need a system with as much capacity for heat and hot water generation. It’s important to remember that investing in better insulation will also reduce your energy bills and increase the efficiency of whatever heating system you have installed. In addition, as if reducing your energy bills and carbon footprint weren’t enough of an incentive, you should check to see if you qualify for any of the grants available for upgrading residential heating systems.


Storage Heaters

A yellow storage heater

Storage heaters use electricity efficiently and take advantage of cheaper night energy rates to heat up ceramic bricks overnight, and then release this energy over the following day. As they use electricity, which is much more expensive per kilowatt than gas, they’re only a cost-effective solution if there is no gas connected to your home.

Storage heaters come in four different models, and in order of increasing cost are; manual storage heaters, automatic storage heaters, automatic combination storage heaters and quantum storage heaters. Prices range from around €300 up to €800, including VAT and installation. Installation costs vary depending on if there was already an existing storage heater, which is being replaced, or whether the wiring will have to be put in for a new one.

Always get at least three quotes for storage heater installation to help make sure you’re getting the best deal.

Manual storage heaters are the cheapest and most basic heaters, but can result in energy wastage as they don't have a thermostat and therefore won’t turn off, even if the room is hot enough to fry eggs on the floor.

In the next price bracket are automatic storage heaters, which have an inbuilt thermostat to avoid the issues of overheating rooms found with manual storage heaters. Then there are automatic combination storage heaters, which have the thermostat advantages of automatic heaters, with the added functionality of an electric convection heater. This means they are ideal for larger spaces, or to top up heat levels if you feel like your storage heater isn’t getting the job done.

Last but not least we have the most expensive option, the spiffily named quantum convection heater. No, it won't transport you to a warm tropical island, but it does incorporate silent fans to aid in wafting warmth into your room, and is actually cheaper to run than the other models. As such it may be worth investing a little more in this case.

Most storage heaters also come with ten year guarantees, and with correct use, tend to last much longer.

Verdict If you’re not connected to any gas source, storage heaters may be a good option for you. If your budget for upgrading is limited, stick with an automatic storage heater for smaller rooms, and consider investing in a quantum storage heater for larger rooms - we’re sure you’ll make your money back in reduced energy costs.


Immersion Heater

A yellow switch with the words on and off

Immersion heaters are only used to heat water, and are a bit like giant kettles in that a conductive element is used to heat the water. They also run off electricity, so we’ll remind you again that if you have gas in your home, a gas boiler could save you hundreds of euros per year, for the same output. An immersion heater should only really be an option for electricity-only households.

Of course if you’re reading this, chances are that you have no gas connection, in which case an immersion heater is a necessity. They can also suit households or businesses where hot water is imperative (such as a hairdressers), as they are not connected to the boiler. This means that you’ll still have hot water in the event of your boiler breaking down.

They can also be easily connected up to solar panels, and if well-insulated, will keep water hot for hours after being switched off. If your house is connected up to solar panels or wind turbines, excess electricity diverted to your immersion heater can mean your hot water will be free of charge!

If you opt for an immersion heater or already have one installed, depending on your personal routine, it might suit you best to be on a cheaper night tariff. That way you’ll have hot water ready for your morning shower, and to wash up dishes from the night before.

And of course you’ll need to consider the perennial question: the immersion heater switch, on or off? While most modern immersion heaters have thermostats and ideally you should be able to leave it on 24/7 as it should regulate itself, we don’t advise this. Unless there is absolutely perfect insulation on the tank, heat loss will still occur and the immersion heater will then use more energy to top up the temperature. This means, you guessed it, higher electricity bills.

It’s best to set a timer if you have a day/night tariff, and take advantage of the cheaper night rates and have a store of hot water for morning ablutions. If you don’t have a timer, then just switch it on for an hour before you need it.

Verdict If it’s too expensive to connect to a gas supply, then immersion heaters which are set to heat at night, and are properly insulated, are a viable hot water source. If you get solar panels installed you can even enjoy the luxury of free hot water.


Heat Pumps

A cross-section of a room with underfloor heating, a tap, and heaters

Let’s consider heat pumps, the king of home energy heating and hot water. Heat pumps work by extracting thermal energy from an air, water or soil source, and compress refrigerant gases to amplify it, giving off a huge amount of heat. This heat is then put to work in your home.

One might think that living in Ireland, there may not be enough heat available outside to use with the pump. However heat pumps are common in Scandinavian countries, which suffer much colder temperatures. In order to install a heat pump in your house, it already needs to be reasonably energy efficient.

This means well insulated, and with double or triple glazing. Your home should also have underfloor heating and low temperature radiators. Heat pumps provide lower temperature heating for radiators, and so will only work well with insulated houses as otherwise the radiator temperature will be too weak due to heat loss. Most heat pumps can be used for hot water as well, barring air-to-air pumps.

When done correctly, heat pumps can eradicate the need for oil or gas and substantially reduce your electricity bills. In fact, heat pumps can heat your home for up to 50% less than an efficient condensing combi boiler. This means that your greenhouse gas emissions and carbon footprint for your household will be markedly reduced.

For every unit of energy consumed by a heat pump, 300% to 400% heating and energy gains can be made.

An infographic showing that 3 units of thermal energy plus 1 unit of fuel generates 4 units of heating or electricity energy

The SEAI also provide grants to upgrade your home heating system with a heat pump. However these grants are only available for pumps which don’t use oil or gas, and they must also be used to heat the house and/or water, and not for hot water alone.

Heat pumps also add to the value of your house as they improve your BER (Better Energy Rating).

Air source heat pumps use external air and are the most common type of heat pumps, being easier and cheaper to install. They most common types are air-to-air and air-to-water pumps. Air-to-air pumps do exactly that - they heat the air in your home. Air-to-water heat both your home and your water.

Ground source heat pumps involve installing a network underneath the topsoil to extract energy. While more expensive than air pumps, they last longer and are more reliable in adverse weather conditions. They work very well if you have a large garden.

Water source heat pumps are the least common as they require access to water in the form of lakes, ponds or rivers. They cost more or less the same as ground source heat pumps to buy and install, and are the most efficient heat pumps. Heat pumps are always on and are more efficient and more economical to run that way. So if you prefer a cooler environment they may not be for you, although most include heating controls to better reconcile with your daily routine and preferences. For example, most people prefer to sleep at cooler temperatures (and it’s healthier!).

Verdict If your house is a relatively new build with decent insulation and underfloor heating, then a heat pump is absolutely the best choice for you. However for older houses, the cost required to upgrade them and then pay to install a heat pump system as well, could mean they're out of reach of many people's budgets.

If you think heat pumps might be a winning heating solution for your home, then contact an independent SEAI registered technical advisor to assess your house and provide an estimate. Keep in mind that if you're put off installing a heat pump due to the amount you'd have to shell out to upgrade your house, you should check to see if you qualify for an SEAI grant to upgrade your home insulation and heating system.


Gas Boiler

A yellow boiler

The average standard unit rate for electricity in Ireland is currently €0.1946, while the average standard unit rate for gas is just €0.062. We can immediately see that using gas for our home heating and hot water needs is less than a third of the price when compared to using electricity.

Types of gas boilers include system boilers, combi boilers and conventional boilers. These boilers can then be condensing or not. Boilers with condensing functions recapture heat that would normally escape, from the flues for example. They increase the efficiency of your boiler by producing more heat for the same amount of fuel when compared with non-condensing boilers. In fact, modern condensing boilers can be 99% efficient at fuel energy extraction.

Some drawbacks of condensing boilers are that any external pipes are more prone to freezing in winter (you can remedy this by pouring hot water over them, and should consider external lagging to prevent it from occuring) and they are more complicated to fix. We recommend getting your condensing boiler serviced yearly to avoid costly breakdowns and ensure they are running safely.

While the majority of modern boilers are condensing, we recommend you make sure whichever boiler you choose does have a condensing function to help you get more bang for your buck. You should also check out the energy efficiency rating for your boiler as it’s worth spending a little extra money when over the long run you’ll see a reduction in your energy bills.

System Boilers

These boilers consist of a water cylinder where the water is maintained at a certain temperature. With system boilers you can use several taps for hot water at once (unless you use up all the hot water, ouch!). The water is heated when you turn on a tap or shower to the hot water setting, and you need to wait a minute or two for the water to heat up.

System boilers provide a middle ground regarding energy consumption when compared with combi and conventional boilers. They are also quick to install and occupy less space than conventional boilers (but not as little as combi boilers). As with conventional boilers, there is some energy wastage from water cylinder heat loss.

Combi Boilers

A cross-section of a boiler connecte to a radiator showing flames heating up pipes and transferring the thermal energy to water

Combi Boilers don’t have water cylinders or tanks, and heat water on demand. You don’t need to find space for tanks or cylinders, or waste energy on maintaining the water at a certain temperature. However they don’t perform well when more than onehot water source is turned on.

As combi boilers only heat water on demand, they are considered to be the most energy efficient type of boiler, but can be complicated to install due to the need for rewiring and pipework. They are the least intrusive boiler when it comes to size. For smaller households, combi-boilers are eminently suitable and could potentially reduce heating and hot water costs by up to 30%.

Conventional Boilers

Conventional boilers have both a storage tank and a cylinder. Due to this they may not be suitable for smaller dwellings where space is at a premium. As with system boilers, you can have hot water from multiple sources at the same time. Similarly, you can also “use up” all the hot water and have to wait for more, although they have a greater hot water capacity than system boilers.

Conventional boilers were the first type of boiler to be used in central heating, and are best suited to houses with plenty of space, including attic space for the storage tank. They are wasteful unless your house is very large and there are quite a few people living there needing plenty of hot water, given the potential for heat loss from both the cylinder and the tank.

Verdict When considering purchasing a gas boiler, it's important to choose the type best-suited to the size of your dwelling, the amount of people living there, and the existing boiler system. In addition, make sure your new boiler is a condensing model. If your area is prone to gas supply disruption then a combi boiler may not be for you as in those situations you’ll have no hot water stored up.


Oil Fired Boiler

An oil refill tanker

Oil fired boilers do require access to oil tanks and so have all of the downsides of being dependent on oil. Namely that you’ll need a large unwieldy tank, and will most likely have to pay for bulk oil deliveries.

Modern oil boilers are similar in function to gas combi boilers and heat up water on demand. However they differ from gas combi boilers in that they usually have some internal storage system for hot water. They are over 95% efficient in converting fuel to heat, and as oil is more fuel efficient than gas, are even cheaper to run than gas boilers. As with gas boilers they require regular maintenance to avoid any potentially dangerous issues arising. Let's not forget that in addition, oil fired boilers will also increase the carbon footprint of your house as oil is not environmentally friendly or renewable.

Verdict If you’re not connected to gas, and have the existing infrastructure in place for oil, oil fired boilers are a good option. However if you have no oil system or tank connected to your house at present, the cost of installation could be prohibitive. As oil is a fossil fuel its price can only go up with time as it becomes more scarce, meaning that it could be unwise to sink money into a long-term installation such as this.


Electric Boilers

Electric boilers are high efficiency as they only heat water on demand, like gas combi boilers. They are also relatively cheap and easy to install in any place in your house, as they don’t require flues or gas piping, just access to an electricity supply.

The downside, of course, is that electricity is more expensive than gas, meaning that no matter how efficient an electric boiler is, it’s never going to beat a condensing combi gas boiler for example. They can also only heat small amounts of water at a time meaning they may not be suitable for larger properties. In areas where power cuts are common you’ll also be left without any hot water.

Verdict Electric boilers may be efficient but are still beaten out on running costs by infrared systems, heat pumps, and even oil boilers (for now). You should only really consider installing an electric boiler if: You´re not connected to a gas supply and it is cost-prohibitive to do so, space is at a premium in your household, and you don’t have enough of a budget to install more efficient options.


Solid Fuel Boiler

A camp-style fire on a bundle of sticks

Fuels used for solid fuel boilers include pellets, coal and wood. Pellets and wood are considered to be more environmentally friendly as they are carbon neutral. However you’ll need to remember to buy the fuel and organise storage space for it. If you opt for a wood boiler, you’ll also need to ensure that the space where the wood is stored is moisture free.

One advantage of solid fuel boilers is that you won’t be affected as much by price increases when compared to gas, electricity, and oil dependent systems. Wood and coal boilers produce a high content of ash which will also need to be disposed of. Pellets on the other hand only produce 1-3% ash so you won’t need to have the ash disposed of as often. However pellet boilers are much more expensive than other solid fuel boilers.

What is carbon neutral fuel?Carbon neutral fuel is when the about of carbon produced by burning the fuel is negated by the amount of carbon previously absorbed by the fuel.

Homes with solid fuel boilers are also better ventilated (due to the chimney or flue), and if you have a stock of fuel there’ll be no need to worry about power cuts. Modern solid fuel boilers have compact attractive designs and are quick and easy to install. They come in steel and cast iron options. Cast iron options have a lifetime of up to 50 years, while steel ones last 10-20 years.

Verdict Cheap to run and energy efficient, a solid fuel boiler could be a consideration if you can get over the initial pricey investment, and you’re willing to be more hands on when it comes to buying your own fuel supply and disposing of residues. If you live in a remote location, this may be a very attractive option.


Infrared

Infrared home heating is a relatively recent addition to the different ways to heat our homes. Many people think of infrared radiation and are turned off by the word “radiation” with all the negative connotations it has. In fact, infrared radiation is perfectly safe and suitable for home use. It simply refers to the sensation of heat, for example when you feel warm when the sun is shining on you through a window. Even humans emit infrared radiation (that’s how those nifty night goggles can see you).


 

Infrared heaters come in many different shapes and sizes for home use, run silently, and can even double up as mirrors and pictures. They heat the surface area of a room and its contents, rather than the air volume (which is how traditional radiators and space heaters work). This then means that warmth is retained in your walls and floors. They can work with gas, oil and solid fuel but electric ones are recommended as they are much easier to install. They heat up much faster than regular radiators, reaching peak heat output in less than 30 seconds.

They are twice the price of regular space heaters and work best when not blocked by obstacles, which can be difficult to achieve depending on the size and layout of your home. They can work with any energy supply and are low maintenance.

Verdict Although an attractive home addition and efficient at heating, infrared radiators would still run off electricity and as such, be more expensive than an efficient gas boiler. They would probably be ideal in spaces which only need intermittent heating, such as bathrooms, but we wouldn’t recommend them for oddly shaped spaces such as L-shaped halls where one normal radiator might be more suitable.

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