The heat pump survey involves measuring every room to be heated including windows, what the building is constructed from, all insulation types in walls, floors and ceilings.
Review the existing heating system - details, size and type of existing boiler, size of the existing radiators, size and design of the existing pipe work. It is vital this is carried with great care and accurate details are recorded to be able to undertake a heat loss calculation and heat pump design.
SiZe Matters heat pump system design is in accordance with recognised industry standards and guidance - MCS MIS 3005-D Heat Pump Design and CIBSE Domestic Heating Compliance Guide
When installing an air source heat pump, the use of existing radiators can be problematic without careful consideration. Correctly specifying the heat emitters, be they convector radiators or Underfloor Heating (UFH) circuits, against the calculated room heat losses for given operating conditions is crucial to ensuring correct heating performance.
While electricity is more expensive than gas, air source heat pumps benefit from exceptional average efficiency rates of around 300%. If that doesn’t sound impressive, we don’t know what will.
There is a range of cost-affecting factors that can shape the price of running an air source heat pump.
Heat Pump Efficiency
Naturally, the more efficient a heat pump is (or the higher its Coefficient of Performance (COP) is), the cheaper it will be to run. There are many highly efficient air source heat pumps on the market. Nonetheless, the heat pump variations from model to model are important when considering what your specific running costs will be after an installation.
Heating Demand
Obviously, the more energy you require from your air source heat pump, the more it will cost to run. What’s more, your home’s heating demand will be linked to the power of your heat pump.
So it may not necessarily be the case that you’ll end up running your heat pump more than a household with a lower heating demand but rather that you’ll be using a more powerful heat pump to meet your demand. Either way, higher heating demand is very much correlated with a higher running cost.
Household and Property Insulation
While heat demand is a key factor, how much heat demand will shape your overall running costs will in turn be affected by how well your home can keep the heat in. In the end, the goal is to heat your house only, not your neighbor's as well.
Why does heat pump size matter?
You might be thinking the bigger the size of your air source heat pump, the better, right?
Well, not exactly. After all, you wouldn’t need an industrial sized gas boiler to heat a 2 bed house!
Air source heat pumps have a rating in kW, which represents their output. For example, a 10 kW rating on a heat pump will mean it delivers 10 kW of heat (based on the outside "design" temperature). Most air source heat pumps range between 4 kW to 16 kW. As a general rule of thumb, the greater your whole house heating needs are, the more powerful you’ll need your air source heat pump.
What size hot water cylinder do you need?
Just as important as getting your heat pump sizing right, is making sure your hot water cylinder can meet your home’s demands. An unvented indirect hot water cylinder is essential for systems with an air source heat pump. That may sound complicated, but it just means that the cylinder has a coil in it which is heated by the air source heat pump. This coil then heats the water in the cylinder.
Generally speaking, a typical domestic household will use around 45 - 50 litres of water for every person. Again though, it’s not always so straightforward. The habits of the people in the household will also need to be considered.
To meet the MCS heat pump standard MIS-3005-D, a heat pump needs to be sized correctly to meet the heat demand of the building.
The standard states that a heat loss calculation should be performed on the building in accordance with standard BS EN 12831:2021 Heating systems in buildings — Method for calculation of the design heat load
This standard specifies methods for calculating the design heat loss and the design heat load.
The BS EN 12831:2003 standard is a room by room heat loss calculation which differs from SAP 2012 which implements a dwelling wide heat loss calculation. The BS EN 12831 standard takes into account the U-values of internal walls and the heat loss or gain rate through each wall into the rooms either side. This is needed in order to work out the heat emitter sizing in each room so that the room temperatures are met. Without a room by room heat loss calculation it could be easy to under size radiators
When installing an air source heat pump the property owner is required to get permission from the District Network Operator (DNO) before making the connection. This is because the DNO, who are responsible for managing the electricity distribution network, need to check whether the local network can handle the additional load from a new heat pump installation. If you install a heat pump without permission, you could be forced to remove it.
DNO applications for existing electricity supplies are handled by the installer. When considering which heat pump partner to choose, this is an important factor to consider.
Navigating the DNO process can be a challenge, and it is a requirement of the MCS scheme to have the DNO permission in place for a heat pump installation.
An air source heat pump generates noise, and it can operate during the night and day. As a result, it has the potential to cause significant adverse effects to people living nearby. Since December 2011 Permitted Development rights allow MCS approved heat pump installations without the need for planning consent.
The MCS020 Planning Standard ensures the proposed location of the air source heat pump outdoor unit has a noise level lower than 42 dB (A) and therefore would not require planning permission from the local authorities.
No matter how simple or complex the question is, I can help. By listening first, I can understand your concerns and needs thoroughly. I can guide you through the entire project and advise on solutions that fit your needs.
As an expert with over a decade of experience, I can address fundamental questions and concerns about the technical and financial aspects of installing an air source heat pump.
With links to manufactures and industry bodies I can answer any questions you may have about government legislation, policy, initiatives, or funding.
The consultation begins with a 30-minute call to better understand your questions or concerns. Then, we can agree on how the consultancy will progress and indicate the ongoing fees.
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