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New MCS heat pump standard should improve performance

Posted by Chris Davis on 30 April 2012 at 11:11 am

Are you thinking of installing a heat pump? Well there’s good news for householders and businesses in the shape of new standards to improve the performance of heat pump installations.

Snappily titled “MIS3005 v3.1a”, the new standard affects all new heat pump systems since 1 March 2012 and is here to ensure consistently high performance for domestic and light commercial applications by introducing more detailed rules for the way heat pump systems are designed.

In truth the changes represent the “best practice” levels that any responsible installer should have been working to in the past anyway, but with these rules now clearly defined within MCS it means that customers should be able more easily compare quotes between one supplier and another and be confident that proposals are designed to a common standard.

So what are the changes? The standard introduces a number of steps which must now be followed:

1.    An accurate heat loss calculation must be produced, to prevent the system being “under sized” and running inefficiently.

2.    A new “100% sizing rule” means heat pumps must be capable of meeting the full heating load down to a specified minimum outside temperature without the use of supplementary electric heaters. This is especially important for the sizing and selection of air source heat pumps - where the output reduces as the air temperature drops - to prevent high running costs by over reliance on electric back up heating.

3.    Where the heat pump provides domestic hot water, the cylinder must be sized correctly for the number of occupants and have a suitably sized heat exchange coil for use with the lower water temperatures heat pumps produce.

4.    Selection and sizing of heat emitters (eg radiators, fan convectors, underfloor heating) needs to demonstrate that they can meet the heat losses of each room at the water temperature the system is being designed for.  A new “Temperature Star Rating” also allows you to see how efficient the proposed system will actually be and what could be done to improve it.  A handy Heat Emitter Guide (clicking this link will download a pdf to your computer) has been produced to help installers and customers with this.

5.    System efficiency performance calculations are now a requirement of all installer quotes and these must be produced using a standard format and calculation method to explain to customers the expected system efficiency and running costs.

6.    For ground source heat pump systems a new guide has been produced for the sizing of ground collectors, which installers must demonstrate they are adhering to, preventing danger of undersized and inefficient ground loops or boreholes.

Ultimately the purpose of MCS is to provide protection to the consumer and the tightening up of the design and installation standards for heat pumps can only help with this, leading to systems that perform well and are as efficient as possible.
So if you’re about to install a heat pump, make sure you use an MCS installer and ask him about MIS3005!

Photo by Bryn Pinzgauer

If you have a question about anything in the above blog, please ask it in the comments section below.

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2 comments - read them below or add one


diggerComment left on: 1 May 2012 at 12:35 pm

Go to France and pick up an air to air heat pump from Brico Depot a 3.8 kw output are £200 and install it will not be a solution for the mid winter but will cover you for spring and autumn.For the bleak mid winter i.e when temps are below 7 c i revert to the wood burner with back boiler which heats the whole house.

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Bob Irving

Bob IrvingComment left on: 30 April 2012 at 11:19 am

It would be really nice if heat pumps had a facility within their controllers indicating what COP they have been operating at over a certain period, say a week. A heat meter would be required on the output flow and a bit of memory in the controller, but considering the price of the things, it would not add too much.

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