top of page
Welcome to Harding Heating's Heating Guides

Harding Heating Ltd is a trusted Gas Safe® registered plumber that installs and services boilers and heating in Shrewsbury, Oswestry and the surrounding Shropshire area.

What type of boiler should I install?

Choosing the right boiler for your house depends on several factors, including the size of your home, your heating and hot water needs, energy efficiency preferences, and budget. While I can provide some general information, it's important to consult with a qualified heating engineer or professional who can assess your specific requirements.

Location factors

Whether your property is located rurally or in an urban area and whether you have gas mains or not on your property are all factors you will need to take into consideration. The space available for your boiler will also be a consideration of what you may be able to install.

Heating cost per kWh vs KG CO2/kWh

If you are looking to help the UK get closer to the Net-zero targets or are looking at low-cost running options is the biggest decision you will have to make. The prices and data in the following charts are from May 2023 and are likely to fluctuate.

Chart displaying green credentials for each fuel type:
kg CO2 per kWh of various heating fuels

Above we can see air/ground source heat pumps (GSHP/ASHP) and some solid-fueled appliances are far better for the environment than our traditional gas and oil-fired appliances. Note that most of us would find it difficult to use/install but kiln-dried logs have the lowest CO2 emissions of all listed, this is due to the fact the trees absorb the same amount of CO2 whilst growing and as long as they are replaced, sourced locally and dried correctly before burning will not fail to be one of the lowest CO2/kWh sources we currently have available. On the other end of the scale are our heating oils/Kerosene, which produce far higher figures of CO2 per kWh.

Many rural houses will have previously opted for an oil boiler installation and might also have a log burner, now if you were in a position to replace the oil boiler with a heat pump then the overall CO2 per kWh from your heating appliances (whether being used in conjunction with a wood burner or not) would reduce by over 60% (this figure will only increase as the UK builds greener electrical generation like wind farms, etc).

Whereas many urban properties are generally built with mains gas supplies and should look to either replace the gas boiler with a heat pump where possible or if possible, replace it with a modern high-efficiency gas boiler. Gas boilers are suitable to run with a 20% Hydrogen blend currently coming through our gas network but there are increasing numbers of manufacturers producing hydrogen-ready boilers which are suitable to run on 100% hydrogen with little to no modification.

For all heat pumps installations, it would be advisable to investigate if a solar PV system could be installed and if used in conjunction with a heat store, could increase the property's green credentials further and likely save money in the long term.

Chart displaying cost per unit for each fuel type:
Heating fuel cost per kWh of various fuels

The above cost per kWh of heat energy chart shows oil/Kerosene to be the cheapest option with electricity the most expensive to heat our homes. Both oil and LPG require further space for a tank or storage vessel to be installed away from boundary fences and buildings so this is not an option in some properties.

As heat pumps use electricity to operate but are 270-400% efficient, this reduces the running cost to that comparable with mains gas or less if used in conjunction with a solar PV system.

Wood burners and wood boiler stoves.

Wood burning boiler stove, log burner efficiency and green rating

Kiln-dried wood is near the money for cost per kWh, but due to most properties not having a suitable means of transferring the heat to a wet heating system and enabling it to be transferred around the property safely and efficiently, it is not often used as a main source of heat in the UK. There are options available but the costs for installation soon start to ramp up. Although properties that have a good source of free wood like farms often utilise this solid fuel for heating and sometimes cooking.

Net zero heating solutions

The above basic diagram shows a heat pump, wood-burning boiler stove, and solar thermal system working together with a thermal store. if sized correctly the solar thermal will provide heat for hot water during the summer months, the heat pump will be the main heat source during the colder months and the wood-burning stove will provide a top-up of heat if/when required. Other safety controls not shown in this system would need to be installed to the wood-burning boiler stove to comply with UK building regulations. Thermal stores can be purchased in a variety of sizes to suit small 1-2 bed properties to much larger commercial applications. They will often be fitted in an airing cupboard or now, sometimes, a loft.

Adding a green energy heat source to a property with a gas or oil boiler.

Gas or oil systems or heat-only boilers used in conjunction with a solar thermal system and a heat store will be a great way to reduce your monthly gas bill during the summer months when the solar thermal system will provide sufficient heat for showering and washing up daily. The boiler will often not be required during the average day between the months of May to September saving money on gas.


There are plenty of options to heat our homes but we are generally limited to 3 or 4 due to property types, sizes, and locations around the country. Most properties will benefit from Solar PV and/or thermal systems, which work well together with other renewable heating systems if you have space for a thermal store or something similar. As the UK gets nearer to a net zero deadline, expect deals, incentives and payback schemes to become more readily available.

For those living in Shropshire and the surrounding areas, feel free to contact Harding Heating to discuss your heating and hot water options. We work closely with other independent installers, each are specialist in their field of work.


bottom of page