We are about to embark on an EnerPHit upgrade to a Warmcell insulated Tradis timer framed house and would appreciate all observations, and comments on our proposed changes. It would be particularly useful to hear if Chris P. Bacon has gone ahead with his planned Panasonic ASHP.

The PHPP assessment that has been carried out indicates that the fabric provides a current space heating demand of 38kWh/m2year and we know that we have to reduce that to 25kWh/m2year.

The preliminary test for air-tightness returned a result of 1.45 ach.

We have a plan, and we are budgeting, changes to replace Velux double glazed windows; the replacement of the MVHR and an incremental campaign to improve the air-tightness. Most of the existing windows and doors are GBS triple glazing. These changes result in a modelled demand of 23kWh/m2year.

The original space heating was done with a single log burning stove in one room and open internal doors. UFH was not selected over the Tradis floor unit. We do not propose to alter the existing floor finishes.

There is no mains gas available in this location, and based on prior experience I would not use bulk tank lpg. Our cooking is likely to be all electric with an induction hob to replace our current bottled lpg experience.

Wall mounted electrical heaters were added to coincide with an expected sale. All DHW provision is by immersion, originally grid powered. In recent years an east facing PV array has been installed with 3.6kW nominal output and MCS output of 2887kWhr/a. This is now used to output to the immersion with a simple switch when the sun is out. There is no remaining roof space for solar thermal. If there were we would probably add more PV. The west facing roof is shaded by neighbouring trees, which are beyond our control.

The installed MVHR is by Regavent with un-insulated Rega flexible ducts. We expect to replace this system with a probable Paul system with rigid ducting. We are not anticipating an inline duct heater as the house is fairly large for two (148sq.m.TFA) and we recognise that very large ducts/very high volumes would be necessary to heat enough air for the whole house. There is no preference for or against air heating but we know it is problematic, and we have no room for insulated internal ducting.

So the likely heating will be with a Panasonic Aquarea 3.2kW ASHP, chosen to meet a peak PHPP space heating load of 2168w. It seems appropriate to match the load to this small HP and let it work as required, over each 24 hour daily cycle, in a structure that already has small internal temperature fluctuations.

The assumption is that the system will be set up to run as required with the weather compensation features available from the ASHP utilised.

This would be attached to low temperature radiators with a probable flow temperature of 45°C.We are comfortable to expect that ‘oversized’ radiators will be needed, and we will probable plan with wall space being taken at 3 times catalogue output at delta 50, with comfort levels being achieved from radiant heat.

But it is too early to say whether the Panasonic claims for integration of output of PV will be sufficient to start and run the HP. Perhaps with high output in summer, but as we will only need DHW, perhaps a Solar iBoost diverter will be enough? The Panasonic Heat Pump Manager looks to be an expensive option as things stand as we are aiming for a simple single zone space heating arrangement. Remote control by Smartphone is beyond our expectations, as are at home most of the time.

The DHW use by the two of us is probably lower than average, but we will size for good provision when joined by visitors (which also provides a good provision when eventually selling).

Following the advice in the Aquarea user guide I am assuming ‘stored hot water at approximately 50°C.’ and a tank sufficiently large to compensate for less cold water mixing when used ‘for washing/showering at 39-44°C.’ The probable tank would be a Gledhill HP210IND. The immersion will suffice to provide timed heating, once a day, to above 60C. This could also be achieved in summer with direct PV heating from cold, with energy being diverted from the PV with a Solar iBoost attached.

Looking forward to your thoughts.
Paul

Thank you Gordon for the feedback. I remember from your 'sweet spot ' thread that landscaping was a priority and I hope that you get the deck completed in time to enjoy the summer weather over in Sweden.

I have looked briefly at the CTC EcoWater, which appears to have been designed to output to the attached tank, and normally from internal ambient air. Having looked at other combined airpump/MVHR devices which share this use of internal air I am not sure that it is helpful to deplete internal heat towards DHW, unless there is one room that generates a disproportionate large amount in the first place.

I suspect, in the absence of further sound advice here, then I will press on with quotes for the 3.2kW Aquarea.

I recognise that Steamy Tea is likely to counsel in favour of generally choosing a larger output HP to overcome the freezing and defrost impact upon nominal performance in real-world peak cold periods, but with a peak load of only 2.2kW I feel that the next Aquarea at 5.0kW would be overkill.

Good luck with the deck.

Paul

Hi Paul

The EcoWater unlike many other integrated tank + HPs has proper frost protection down to -10C making it suitable to duct the air supply to it from outdoors. I also would never consider to use one of these types of heat pumps with the air supply from the internal space. I'm also not a fan of exhaust air heat pumps.

Here in Sweden the EcoWater is priced at approx. 1750GBP which makes it great value for a 270 litre tank plus heat pump. Granted it is not as efficient as the Panasonic but at probably half the total installed cost I doubt you would ever save the difference. Pricing in the UK may alter that however.

Hi Gordon,

Posted By: Chris P BaconHere in Sweden the EcoWater is priced at approx. 1750GBP which makes it great value for a 270 litre tank plus heat pump. Granted it is not as efficient as the Panasonic but at probably half the total installed cost I doubt you would ever save the difference. Pricing in the UK may alter that however.

I will look in greater depth at the cost here in the UK, and the potential integration with our radiators.

If you decide to invest in an ASHP are you now firm on the choice of the EcoWater for your home?

Paul