Plumbers vs Heating Engineers – What does your project need?

A Chamonix case study

I was called to a chalet this week to look at a heating system that wasn’t working correctly. Not enough heat in some areas, too much in others. The system was brand new, installed very recently. I asked where the original installer was with this issue and they had already visited the installation, along with the electrician to ‘resolve’ the problem.

On further questioning, (and without mentioning any names as it’s a small town), it turns out that the plumber (Plombier, Chauffagiste, RGE registered) that installed the heat pump and underfloor heating didn’t know how to set up and balance the underfloor heating. He pointed at the electrician, who confirmed that the room thermostats were working, and the result was that neither of these companies could resolve the issue in a visit to the chalet.

The client had a service contract with the heat pump manufacturer to look after the heat pump (which is an excellent move), but this does not include the underfloor heating. When I asked the client who was making sure that the heat pump was running as efficiently as possible to meet how the underfloor heating was designed, it was clear that the underfloor heating did not have a detailed design to meet each room’s heat loss. Neither of the plumber nor the heat pump manufacturer has given any thought to the overall design as regards optimising the energy consumption of the chalet. The equipment has been installed, but not designed to work as an integrated system. The heat pump was running at a relatively high flow temperature, potentially up to 10 degrees to hot (at design outside temperature) leaving 25% efficiency on the table.

The installation as a whole is excellent, everyone involved in the installation has done a great job of installing the equipment, and the local companies involved have earned justifiably great reputations. The pipework is beautiful, neat, insulated and has all the necessary safety and security elements that would pass an audit by the RGE police, so what’s the issue here?

In my opinion, the problem is that there was no heating engineer involved in the project to ensure an overall success.

·         The underfloor heating was installed to a generic standard (150mm pipe spacing) rather than designed to each room’s heat loss. This has made it difficult to balance for even heating (I got pretty close, but it took a day with digital temperature probes)

·         In the absence of an underfloor heating system design, nobody knows how to run the heat pump (Weather Compensation curve), so it’s left entirely to trial and error to optimise the efficiency. As such the system has been left running hotter and using more electricity than it otherwise might.

·         Room thermostats and actuators had been fitted on 8 of the 15 underfloor heating circuits, whilst this can be a way of reducing temperature in certain rooms; it does so at the cost of removing system volume. This in turn can lead to more stop-starting (short cycling) of the heat pump, further reducing its efficiency and shortening its life.

In my view, this homeowner has paid for a system and has been left owning a number of well installed components, without the integration that truly great heating systems need to function efficiently.

At Alpine heating we own the entire heating system design, from working with the construction team to select insulation and building materials, through to ensuring a robust and integrated system design, leaving nothing to chance to ensure an incredibly efficient result.

Photo not of installation concerned - for illustration of heating system balancing