Answer: At 300% to 500%+ efficiency, heat pumps are the most efficient way to heat an off-grid home. Precise financials depend on property heat demands, insulation, and more. Biomass boilers offer an efficient heating method with a low carbon impact. Electric only heating is the most expensive option for off-grid heating. Oil and LPG are also costly and carbon-heavy.
For more detailed information about costs, savings, pros, cons, and efficiency ratings, keep reading this article below. We list the various ways to heat your off-grid home.
Efficiency and off-grid heating
Central heating is the most commonly-used form of heating in the UK. This method of heating requires a mains gas connection and boiler. The heated water is then piped toward the radiators of the building, heating up the spaces within.
This system also supports heated water for bathing or washing, which will be fed to the taps. However, the use of boilers for central heating systems at home can account for up to 60% of total energy usage. There also some homes that use electricity for heating. However, this too can be carbon-intensive, pricey, and very inefficient.
If you want to reduce your carbon footprint and save on heating costs, it is important to look for other heating and hot water systems. Ideally, you should choose a system that utilises the least amount of energy. But neither should you compromise the system’s ability to keep your home warm. Before you start your new-build or renovate your home to incorporate an energy efficient heating system, you need more information about the heating options available to you.
Your heating options
There are three components for heating systems: heat source, method of distribution, and the type of heat emitter. The most common heat sources in the UK include gas (the most common one), LPG, oil, electricity, coal, biomass, solar, or a combination. In the UK, water is the most common form of heat distribution, which is also known as the “wet system”.
Underfloor heating is also becoming a very common way of heating properties the UK. Pipes laid within the floor act as a ‘big radiator’ providing the heat needed to keep the room warm via hot water distributed through the coils of pipe. Underfloor heating is often recommended for heat pumps, as designed properly they can deliver excellent heat output at lower temperature water. However, heat pumps can work with radiators just as well, or systems designed with a mix of underfloor heating and radiators – it’s all about the design!.
An underfloor heating systems is recommended for homes or buildings with adequate insulation and less air exchange, due to the low-temperature heating. The ideal way to use the underfloor heating system is to turn it on for an extended period of time. This is great for buildings with continuous occupancy.
On-grid heating
A quick nod to the options for on-grid heating, first. We won’t go into detail, but this provides good context and points of comparison.
Since the UK experiences chilly weather throughout the year, a heated home is essential. As the different types of heating systems are outlined above, you will realise that there are two common types of fuel sources: gas and electricity. These are standard options for UK homes which are on the mains grid.
However, these two are miles apart in terms of the price per unit. To give you an idea, heating systems powered by natural gas cost on average 7.4p/kWh and rising in comparison to electricity which can range from 16.7p/kWh to 28.3p/kWh. This must be considered at the earliest possible stage if you’re on-grid.
Off-grid heating
About 15% of the homes in the UK are not linked to the mains gas grid. This makes heating a more interesting issue, since gas generally offers the most cost-efficient way to heat a home. If a home isn’t on the grid, this no longer holds true.
In addition, other issues could arise with older properties, which can add to the cost and make heating really expensive. Thankfully, you can now find a wide range of economical options if you have an off-grid home. Some of the most common types of off-grid heating alternatives include the following: LPG and oil boilers, biomass boilers, solar thermal panels, and heat pumps.
LPG and oil boilers
For many decades, off-grid homeowners have relied on LPG, along with oil, to heat their homes. It is used for heating, cooking, and in vehicles – but is also one of options for off-grid domestic heating. Liquefied petroleum gas (LPG) can be stored in a canister or large tank, ready for use.
The system works by burning either fuel in order to produce the energy needed to heat water, which is then used to feed the radiators and to supply the tap. Nonetheless, these are expensive and carbon-heavy options for an off-grid home.
Pros:
The use of LPG and oil boilers are advantageous because the fuels are widely available and the service infrastructure is well-established. While it’s not a completely “clean” energy, LPG is cleaner than some other fuels used to generate heat. According to PriceYourJob, burning LPG produces less sulphur, nitrogen oxides, and carbon dioxide (33% less carbon dioxide than coal and 15% less than oil).
Cons:
The higher fuel cost is the main downside for choosing these kinds of boilers. The extra cost of buying (or renting) a storage tank for the LPG can be a downside, too.
Costs:
A new oil or LPG boiler will cost between £1,500 – £3000. There is a variety of brands on offer for each option. In addition, according to Boiler Guide, “on average you can expect to pay anything from £800 – £2,000 for the labour and installation of your new boiler.”
Efficiency:
A new condensing oil boiler will have an estimated efficiency of around 93%. An LPG powered system will usually have an efficiency of over 90%.
Biomass Boiler
Another example of an off-grid heating system is a biomass boiler. This is highly suitable for homes without mains gas. However, the upfront cost can sometimes be a barrier. But this is a one-time cost, and you would be able to earn it back through the government incentives (RHI) and significant utility bill savings.
Pros:
You can use natural materials like logs and wood pellets to produce heat. This means that the system generates heat using natural and renewable resources. It is cheaper to run, and better for the environment.
Cons:
The large upfront cost might not make it suitable for all property owners. Furthermore, the systems need more space than traditional boilers and you need to take delivery of and store the fuel nearby. If you don’t have an automated system, you will need to manually supply the boiler with fuel.
Costs:
The initial cost of a biomass boiler is quite expensive. The smallest domestic systems start at £5,000, but this might not be suitable for your property (or properties). Indeed, the installation of a larger auto-fed biomass boiler could work out at between £10,000 – £20,000.
Wood pellets cost around 9.9p/kWh. These cost are much more stable than oil and gas, because they are not affected by import/export prices and other global events which affect fossil fuel costs.
Efficiency:
Biomass boilers operate at an efficiency of between 89 – 91%. This is comparable to conventional boiler systems (as we saw earlier with LPG and oil efficiencies).
Heat pumps
Renewable heat sources should be the primary ambition for homeowners, and this is where heat pumps come in as a great option. Heat pumps are particularly suitable for off-grid properties in the UK, and are emerging as the frontrunner for renewable heating.
Currently, there are two types of heat pumps that are popular:
An air source heat pump (ASHP) uses the principle of vapour compression refrigeration to absorb heat from one source and release it in another. Put simply, an ASHP absorbs heat from the outside air. In terms of domestic heating, it can also be used to produce hot water (as much as 80 degrees Celsius). Even in colder climates, this system has the ability to extract useful heat from minus 20 degree ambient air.
A ground source heat pump (sometimes labelled a geothermal heat pump) is another renewable heating source for off-grid properties. This system harvests heat from below the surface of the earth, which is converted into energy for heating and hot water. It is an innovation that takes advantage of moderate temperature to remain energy efficient. These systems can work with deep vertical boreholes, or shallow trenches.
Both of these systems use some electricity to operate, but you can pair them with solar PV and battery storage to minimise costs and carbon.
Pros:
Whether you choose air source or ground source heat pumps, it is considered as one of the best off-grid heating options with the highest efficiency.
You can enjoy high energy efficiency and more effective indoor heating. It also operates more quietly and requires minimal maintenance. Finally, you won’t ever have to worry about carbon monoxide poisoning. Read our article about the benefits of heat pumps for more information.
Cons:
The main downside to a heat pump is that they require the installation of an indoor and outdoor component. GSHPs need a lot of outdoor space. ASHPs need a clear area on an external wall for the fan unit. Properties need space for a small plant room, although there are workarounds if this is impossible.
Costs:
The cost of installing an ASHP ranges between £9,000 – £15,000. The cost of installing a GSHP is between £12,000 – £20,000 with additional costs for ground works. The running costs are relatively cheap compared to other options, due to the fact that only a small amount of electricity is needed for them to operate.
Efficiency:
Heat pumps (air and ground source) are two of the most efficient systems around. A heat pump can provide an efficiency of up to 300% to 500%+, since they do not generate heat. Instead, heat pumps transfer natural heat from the air or ground.
Solar Thermal Panels
Solar thermal panels are suitable for hot water, but less suitable for space heating. They can, however, be used to preheat space heating systems. By and large, solar thermal panels must be considered as an option for hot water, with support from other systems.
Pros:
You will save money on bills and reduce your carbon footprint.
Cons:
Solar thermal panels often struggle to provide the right level of heating and hot water all year round. This means that they are combined with traditional or biomass boilers to ensure performance in the colder winter months. You need to consider whether your existing system is compatible with solar thermal, and understand the associated costs of integration.
Costs:
Solar thermal systems typically cost between £3000 – £6,000 to install.
Efficiency:
Solar thermal panels are typically 70% – 90% efficient.
Summary
Every homeowner’s needs vary, but there is no denying the importance of an efficient heating solution. Off-grid homes might initially look at their situation as difficult. However, this puts you in a good position to seek out alternatives that are not only less expensive (in the long-run) but are also more energy efficient. If you want to switch to a greener way of life with less heavy bills, you need to look at the renewable off-grid options closely.
This is why heat pumps are generating a lot of buzz, as the efficiency offered by this type of system overpowers any rivals. The running costs compared to other systems is also featuring large at the moment with the price caps and energy security issues, and the improving financial assistance is making heat pumps more desirable.
The Boiler Upgrade Scheme for England & Wales launched on the 1st April 2022 by the government to encouraged homeowners and self-builders in the UK to opt for renewable heating sources. This provides an upfront payment, in the form of a redeemable voucher, of £5,000 for Air Source Heat Pumps and £6,000 towards a Ground Source Heat Pump. Applications are made by the installer are opening on 23rd May with all installs after the 1st April being eligible to apply.
In Scotland the Home Energy Scotland Loan provides interest free loans for a variety of energy efficieny measures with £10,000 available towards the cost of installing a heat pump. The cash-back scheme offers upto 75% of this back as a lump sum once installed.
With energy with prices going up and the threat of Carbon Taxes looming, heat pumps provide the ‘no-regret’ answer for providing energy efficient, low carbon heating and hot water today.
Whichever system you choose for heating your home, the most important thing to remember is to work with an experienced professional. Professional installers of renewable heating systems can guarantee that you will be able to maximise the benefits offered by the system.
IMS Heat Pumps
We are your renewable heating specialists. With decades of experience and thousands of projects under our belt, you are in safe hands. If you need help on a self-build or renovation project, or if you are considering a switch to renewable heating, get in touch.
You can contact us online, or call 01738 827 244 or 0114 327 0100