Though one of the simplest ways of working an air supply warmth pump is to run it on the lowest temperature attainable, excessive temperature warmth pumps at the moment are extra broadly obtainable and will be thought of a great choice for older houses the place decrease temperatures may not suffice.
However, do the additional working prices that include greater temperatures offset the vitality effectivity benefits, or are they nonetheless value contemplating?
Power knowledgeable, David Hilton explores why the upper move temperature is not at all times a difficulty and the way to be sure to nonetheless acquire most effectivity and vitality financial savings from one of these heating system.
How excessive temperature warmth pumps work
Because the introduction of R290 as the commonest alternative of refrigerant for warmth pumps, propane (R290), as a result of nature of what it’s, will be compressed to greater temperatures than a few of the gasses which have beforehand been utilized in air supply warmth pumps.
Temperatures of as much as 75°C are fairly attainable, whereas beforehand warmth pumps have been usually restricted to 55°C, that means owners needed to weigh up the variations between low vs medium vs excessive temperature warmth pumps.
Fashionable air supply warmth pumps nevertheless now use variable velocity compressors, that facilitate modulating energy outputs to match the houses warmth demand. And, whereas the Microgeneration Certification Scheme (MCS) – which units the requirements for warmth pump installations – beforehand restricted the move temperature to a most of 55°C to fulfill effectivity necessities, now that trendy warmth pumps can produce greater temperatures and nonetheless meet the minimal effectivity, we are able to subsequently convey greater temperatures into the house.
However, simply because a excessive temperature warmth pump can produce excessive temperatures, does this imply it ought to, and the way usually are you more likely to want them?
Advantages of a excessive temperature output
Though in a new-build, properly insulated, vitality environment friendly residence you’re unlikely to want excessive temperatures out of your warmth pump, it isn’t the identical in older houses the place an air supply warmth pump is perhaps thought of as a alternative for a boiler powered by fuel or fossil fuels, and may lead folks to query are warmth pumps appropriate for previous houses?
A central heating system was usually designed for a boiler led system with excessive temperatures. That implies that your radiators and pipework have been specified for fast heating of the room – hotter temperatures imply that the warmth transfers to the room faster.
Nonetheless, while you design a warmth pump heating system, it’s an MCS requirement {that a} room-by-room warmth loss calculation is carried out.That is as a way to decide the quantity of warmth that the room requires in a selected space, and at a selected design temperature.
For instance, in the event you stay in Plymouth then the design temperature is -1.2C however in Edinburgh (as a result of it will get a bit colder there) the design temperature is -3.4C. The warmth pump should then be specified to ship the required quantity of warmth to the house, at that exact temperature.
In all circumstances, the most effective and most effective design for a warmth pump system is to run the warmth pump on the lowest temperature attainable whereas nonetheless delivering the correct amount of warmth to the house.
However, as a result of trendy air supply warmth pumps can modulate, they’ve a software program in-built that screens the ambient temperature exterior and lifts the move temperature to the house because it will get colder exterior.
So how does this profit the home-owner?
In current houses, it means now you can be provided a alternative in case your current radiators usually are not large enough for the low temperatures required to run a warmth pump effectively.
The installer, as an alternative of suggesting you alter all of your radiators – which often means growing the dimensions and or amount of them, can as an alternative specify a excessive temperature warmth pump.
After all, the offset of that is that whereas this may seemingly offer you a less expensive general set up value, it means you’ll have a barely greater working value.
The second profit of upper temperature refrigerants is that you would be able to retailer water in your scorching water cylinder at greater temperatures, that means that you would be able to have a smaller cylinder. A 300 litre cylinder at 50°C has the identical quantity of useable water as a 250 litre cylinder at 60°C and a 210 litre cylinder at 70°C.
Nonetheless, bear in mind that in the event you retailer your scorching water at greater temperatures it’s extremely really useful that you simply match mixing valves to your scorching water retailers (faucets) to keep away from scalding. It is a constructing laws requirement in new construct dwellings, however a suggestion in current houses.
Set up prices vs working prices
Whereas an installer will have the ability to share extra particular calculations, normally they are going to use comparable calculations to determine how a lot further your working prices can be versus the prices of upgrading your radiators.
For example, if as a way to optimise the warmth pump you would wish eight new radiators and some lengths of pipe, given the disruption, supplies and labour we are able to estimate the price for this might be round £3000.
If the warmth pump solely wants a few levels greater temperature for many of the 12 months, and the a lot greater temperatures for say 5 days a 12 months, the extra value of this is perhaps estimated at £150 a 12 months.
It is then a case of dividing the price of upgrading your radiators by the additional working prices, to see which sum sits most comfortably with you. On this instance, you could possibly run at these elevated ranges for 20 years earlier than you reached the sum of £3000.
After all, these usually are not actual figures and an installer will have the ability to offer you extra lifelike numbers so that you can work with, however you possibly can see the reasoning.
What it additionally would not keep in mind, is that as you redecorate rooms or full extra home renovations, you even have the choice to improve the prevailing central heating system over time, subsequently bettering the warmth pump general effectivity and lowering your working prices even additional.
In conclusion, it is vital to keep in mind that excessive temperature warmth pump choices are precisely that: choices. The professionals and cons of every mannequin must be thought of, and whereas the general finest environmental answer will at all times be the low temperature, optimised set up, that might not be the ‘finest’ answer for you.
Select your installer rigorously, do the maths after which make the knowledgeable choice. A really barely much less environment friendly warmth pump system, with the potential to enhance over time, that does not require main disruption and capital value, and that’s nonetheless eligible for the £7500 Boiler Improve Scheme grant, might be simply the ticket.
