Kassgas Ltd

Combi Boilers VS Air Source Heat Pumps

Combi Boilers Vs Air Source Heat Pumps? You may be wondering what are the benefits or drawbacks of having each system installed. So that’s exactly what this blog post is set out to help with! Not every system is perfect and every home has advantages and disadvantages to each system. I will outline the main pros and cons of each system that will apply to 99% of the UK Housing Market. To understand them however I will run through exactly what each system does and how it does it.

What Are Combi Boilers ?

What are Air Source Heat Pumps ?

A combi (or combination) boiler is by far the most common type of boiler. A combi boiler system’s simple design requires little space in your home and supplies hot water directly to your taps or radiators without the need for a storage tank. It does this by using different flow paths inside the boiler to separate when heating and hot water are on in your home.

Combi Boilers are typically run on Natural Gas that is supplied to your home by who you use for your energy suppliers. They can run on different sources, such as Liquid Propane Gas ( LPG ) or Oil. Combi boilers are the most common source of home hot water and heating in the UK. Combi boilers began in the market in the 1990s and quickly became a fast favourite for the industry. They eliminate the need for large hot water cylinders in your home freeing up large spaces in even the smallest homes in the UK. Removing large hot water storage spaces in homes massively increases homes’ efficiency ratings and therefore brings the UK’s goal of reducing carbon emissions massively.

Combi Boilers remain the installer and customer favourite to be installed in homes, with their small size and easy-to-install nature with no immediate actions required to be fitted in your home, unlike Heat Pumps that normally require additional works such as Cavity Wall Insulation or Triple Glazing. 

Air Source Heat Pumps ( ASHP ) use temperature from the ambient air to heat a gas inside themselves that reacts to pressure, when compressed or squashed the gas produces heat. The gas is highly sensitive and even a 2ºc difference in ambient air could make a difference to improve efficiency inside the unit as it is magnified by the refrigerant.

Heat Pumps use no fossil fuels for the production of heat, they rely solely on electricity to keep them running thus making them one of the UK’s best options to reduce our carbon footprint in the home heating sector. ASHP are fitted to the outside of your home or building and absorbs temperature from the air it is placed in. They then transfer that heat produced from the gas into water that is directed into your homes to heat either your radiators or Hot Water Storage System. ASHP are unlike combi boilers in that they don’t give out instant hot water. They require a large hot water cylinder to be installed alongside the unit to give you hot water which can depend on the needs of your home, and take up a large amount of space. 

Any Heat Pump Installation can require an unknown amount of other work required to make the home more suitable for the system. Triple Glazing or Cavity Wall Insulation are the most notable solutions as they will keep the heat that has been produced inside your home. This can increase the costs of having Heat Pumps Installed in your home. 

What Our Engineers Think

Matthew Kassim – Kassgas Director

“Air Source Heat Pumps are undeniable in the fact that they cut carbon emissions produced by homes in the UK. There is no doubt that for the future a suitable renewable method for heating homes in the UK is needed, ASHP are a great solution… For the time being. With many factors affecting where a heat pump can be installed, many homes wouldn’t be suited for this kind of system. With costs being so high for the newly produced technology there is a small % of families in the UK who could afford & benefit from having a heat pump installed.”

Billy Boot – Lead Engineer

“Heat pumps are still a relatively new technology that has had fast-tracked improvements due to publicity. There are many many advantages to having heat pumps installed. For me they are perfect for the new build infrastructure that we have in the UK, being able to build houses that are made for this system is the best and most efficient way we can make ASHP work. The matter still stands that there are too many factors in having an ASHP fitted in a standard 2-bed terraced home which you can find anywhere in South Yorkshire. Heat Pumps are here to stay, a lot of advancements are needed to make them a viable solution. Combi Boilers have been around for 30 years, with improvements made to existing models being made sometimes every 6 months. These kinds of advancements are needed for the heat pump market, until then combi boilers are still the most cost-effective way of heating water in homes and with millions of homes in the UK. I would estimate combi boilers are suitable for between 80-90% of UK homes, Air Source Heat Pumps are suitable for around 50-60% of homes. We need a universal solution.”

Contact Us Today

Contact Details

Location :

1 Netherfield View, Rotherham, S65 3RB

Email :
Phone :

0330 058 9419

Gas Safe Registered

We are a Heating and Plumbing business based in Rotherham and Chesterfield. Our aim is to create a partnership for life with all of our customers by providing only the best customer service paired with honest and fair pricing.


1 Netherfield View,
S65 3RB

Call Us On : 

0330 058 9419


Mon-Fri: 7:00am – 7:00pm
Sat: 9:00am – 5:00 pm
Sun: 10:00am – 2:00pm

*Kassgas Ltd, company number 11765642 is an Introducer Appointed Representative of TradeHelp. Our firm reference number is 925968. TradeHelp is a trading style of Tradehelp Ltd, Marchwiel Centre, Bryn Lane, Wrexham Ind Est, LL13 9UT, registered in England (03712438), authorised and regulated by the Financial Conduct Authority (firm reference number 697812). TradeHelp are a credit broker, not a lender, and offer loans from a small panel of carefully selected lenders. TradeHelp do not offer financial advice and do not charge you for credit broking services. All loans are subject to status.
Website Designed by Example Designs – Icons by icons8