Options for Ducted Heat Pump

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jonathan18

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#1966949 2-Mar-2018 10:36

Daikin. I think at the time there were few brands that had zone control built in to the main controller (which therefore allows zone control via timer, remote access etc) other than Daikin. This may be different now.

I do suggest reading that first thread I linked to if you haven’t already, as it covers many of the traps for young (new) players - being forewarned of these is to be forearmed! Hence my comment that I’d do it again, but would know what I’d do differently.

lokhor

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#1966953 2-Mar-2018 10:48

I think the supplier we have (which we can't change) prefers Daikin so not really any option in that regard. I have sent an email asking about vent types, sensors and R rating on ducting. I'm a bit worried that they have specified a unit that is too small for the house. It's 195m2 with 35m2 of that being a garage which is not heated. They have only specced the 12.5KW heating unit.

All comments are my own opinion, and not that of my employer unless explicitly stated.

jonathan18

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#1966963 2-Mar-2018 11:13

Well, modern houses are far better insulated than old houses, and often have lower studs, so surely the energy requirements will be lower? Ours is a 16kw unit for a 160m 1920s house, most of which has a 3m stud. That said, if there are no particular downsides to a larger unit and having that will result in quicker heating I may be tempted, but sometimes doesn’t the efficiency drop with larger units?

I’m not trying to turn you off Daikin, more just go in eyes open and to the features and limitations of the various options. They got rid of the disastrous tablet-based control unit that we have, which is great news. I think the bigger issue is, as you’ve covered off, ensuring appropriate placement and size of vents, types of vents, location and numbers of sensors. The other biggie I reckon is ensuring the system is balanced, both between zones but also at the individual room level. This is why I’d look at using a company next time with experience in the commercial sector, as I assume they’d be used to this stuff - most domestic installers are used to doing back-to-back installs, which has none of the complexity of designing (and installing) a whole-of-house solution.

timmmay

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#1966971 2-Mar-2018 11:26

Efficiency can drop with larger units, but if the unit is undersized and will work harder at lower efficiency anyway.

My old but well insulated house has two heat pumps, 10kw Fujitsu and 7kw Daikin (I like the Daikin better). If we leave them on 16 hours a day they're plenty big enough even for the coldest nights, but if we let the house get very cold then try to heat it they run pretty hard. 12.5kw is probably sufficient if you leave it on most of the time during winter.

lokhor

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#1967642 3-Mar-2018 20:24

Thanks for all the advice. Going to wait and see how they respond to my questions and go from there. I'm still a bit torn as to whether or not zoning is worth it, especially since I don't think it will be smart zoning, just control of sets of vents.

All comments are my own opinion, and not that of my employer unless explicitly stated.

N0pe

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#1981735 22-Mar-2018 21:27

I realise I’m joining this chain late, so I hope someone is around to offer some thoughts. I’ve got a 1950s house that until we recently bought it had been a rental for (probably) decades. It’s quite tired.
It needs ventilation and heating.
We want to install a ducted heat pump. We have underfloor access that I think (hope) will be sufficient to have underfloor ducting.

I read earlier someone suggest getting a fresh air intake for their heat pump. It prompted me to wonder if adding a fresh air intake would do the job of a ventilation system as well as heating the house.
I realise it’s not as good as an integrated balanced pressure ventilation system with a heat pump (as per Mitsubishi and Lossnay system), but we have had about 5 ventilation installers round to quote and all bar one recommended a positive pressure system, despite us originally seeking quotes for a balanced system. The remaing quote only offered balanced systems.
Given positive pressure systems are just ‘a fan with ducting’ (quote from installer) surely a ducted heat pump system with a fresh air intake would do both jobs?

Having said that, one question I have is, whether having floor vents would affect the ventilation side of things?

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