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Air source pump with MVHR

(8 Posts)
Purpletop Tue 04-Apr-17 11:47:48

We recently bought a property that had is eventually be a new build. I mean that the shell of the house and windows and outside doors have been done, but the interior is yet to be finished. We hired a project manager to help get a builder engaged and guide us through the process. He's recommended a specific company for MVHR and another for underfloor heating.

We then had a disagreement with the project manager and changed to a different company. The MVHR people remained engaged but the new project managers suggested we replace the underfloor heating company and they offered two alternative providers.

The original provider was suggesting the use of a Niebe air source pump and a large 400l cylinder based on calculations for air tightness 4. The other providers advised the use of an Ecocent 25kw pump, a buffer tank and two 300l hot water cylinders, whilst the others suggested 2 x 17 kw Mitsubishi pump with 2 x 300l cylinders.

The new project manager was unhelpful as to which is better of the latter two. As it happened, the one with the Mitsubishi pumps is unlikely to succeed because their installation would mean moving MVHR installation, which we won't do.

So we are now looking at Ecocent pump. From what I read online it seems that they are effective in summer but struggle in the winter without aditional heat supply such as a wood burner. In addition, it seems that there are some corrosion concerns around anodes after 1 year of use and the cost of the annual service is very high (£400).

Has anyone used Ecocent with MVHR for underfloor and water heating? If so, how did you find their performance in the winter, particularly for heating?

Thank you

PigletJohn Tue 04-Apr-17 13:29:59

no, but I think you are referring to the fact that air source pumps, which work by chilling the outside and warming the inside elements, tend to frost up or clog with ice in winter, because they take the already-cold outer element below freezing point.

I've known people complain that this means they stop working when you need them most.

I have no personal experience of it.

sluj Tue 04-Apr-17 13:38:49

Just make sure there is a company near you that can do the annual service and any repairs. I understand they are few and far between

bojorojo Tue 04-Apr-17 17:16:49

We have two Mitsubishi air source heat pumps for a large 5 bed house and a flat above our garage and a swimming pool. Partial underfloor heating and partial radiator in the house and 5 bathrooms but not all used at once. We did have one pack up but other kept running ok. We have wood burners in two lounges but rarely use them. Only when it is below freezing for a few days.

Take out a service agreement. We also have an immersion heater but only use that when we have a house full and that's rare these days.

We had oil before and a very narrow access for the oil tanker so it had to use the neighbour's drive to get the hose to reach. We needed another form of heating and no gas here! So far the air source heat pumps haven't saved much because the price of oil is relatively stable at the moment but they are working well and definitely don't ice up! We had them installed in 2010.

shanghaismog Tue 04-Apr-17 21:31:06

We have an Ecocent to run our hot water only (which works great). I'm having great difficulty booking a service that is going to cost a huge amount. We did not fit a heat pump at the start of our passive build (although might soon as UFH is such a treat on the toes) as they massively over specified the system - UFH upstairs and downstairs for a passive house! I'm not impressed at all and actively trying to find someone local to service it.

In general an ASHP should be fine to run UFH as you only need such low temperatures and an exhaust air pump should be fine for hot water, based on our (limited) experience.

Good luck...

Purpletop Sun 09-Apr-17 19:38:56

Thank you for your help. I'm keeping my fingers crossed on this one. It's so expensive to install UFH ground and first floor, as the house is quite spread out. If something goes wrong, the thought of wasted monies drives me crazy!

Purpletop Sun 09-Apr-17 19:42:07

Thank you, Bo. Our project manager is exasperated with how involved we go on this issue, he said that all their clients want to know is if the heating works and leaves to them to chose providers and design.

I wish I could too - but if no one is explaining to us which is better, we have to understand it ourselves. It's a big expense and I don't want a cold house despite it.

shanghaismog Mon 10-Apr-17 16:06:15

Be careful of ongoing expense, as our annual service is going to cost £400 and that's without the ASHP!

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