Hot Water Heat Pump for Underfloor

Forums › Home Workshop DIY › Hot Water Heat Pump for Underfloor - Radiator Heating

path

3 posts

Wannabe Geek

#282695 6-Mar-2021 15:08

Gooday,

I have a house with underfloor and radiator heating driven by a gas boiler. Considering installing a hotwater heat pump which has become more available in 2021 since I had the house built in 2013.

Does anyone have experience using Hotwater heat pumps (also called air-to-water heat pumps) for heating underfloor and radiators? and the cost of these hot water heat pumps?

The underfloor downstairs and radiator upstairs heating are great but the control systems between the gas boiler and the heating units have given trouble from Day 1 and as a result leading to high energy costs.

Any advice or experience would be appreciated.

SomeoneSomewhere

1804 posts

Uber Geek

Lifetime subscriber

#2669276 7-Mar-2021 02:44

It's a pretty niche market here so you're going to see a lot of markup anyway, and have trouble finding companies who know what they're doing and can troubleshoot. Even more so than with gas underfloor.

Fixing your controls is likely to be far, far easier than completely replacing the heat source and trying to make it work with the existing control systems.

Curious what you have and why it's not working?

Jiriteach

1119 posts

Uber Geek

ID Verified

Lifetime subscriber

#2669291 7-Mar-2021 08:21

Would be better for you to replace the control and thermostat between the heating units and the boiler. What system are you using?

I moved all of ours including 10 x radiators in each rooms to the Danfoss system. Expensive but outstanding. All app controlled and individually boiler triggers.

-- opinions expressed by me are solely my own. ie - personal

snnet

1410 posts

Uber Geek

#2669292 7-Mar-2021 08:29

Enquire the company "hot water heatpumps" - made in NZ, excellent quality and very efficient - see if they have something that suits you

path

3 posts

Wannabe Geek

#2669360 7-Mar-2021 10:07

Thanks @SomeoneSomewhere and @Jiriteach.

The system was designed by HeatIQ and installed by Carrington Plumbing. Heat source was a Vokera condensing boiler. The controls divert hot water from the boiler to the hot water cylinder or the underfloor manifold or the radiators based on thermostats upstairs (for radiator) and in each of the 7 zones for underfloor heating.

The actuators controlling the valves failed and the controls have been ineffective, and the boiler failed after 6 years and the plumber said it had to be replaced and was replaced. Since then the controls are totally defunct. Haven't found anyone who can fix this.

Can you provide any information on this Danfoss system?

Given this situation and the advances in hot water heat pump technology was wondering if that would more worthwhile investing in, with a view that possibly solar can provide some energy for the heat pump if I decide to have some PV panels as a next step?

Previous Geekzone comments in 2013-2016 have indicated that a hotwater heat pumps would be about $3.5k, whereas suppliers I talk to now talk about over12k to $20k. I would have expected prices of these would be coming down because it is a relatively new technology?

Any suggestions and advice re the controls and the heat pump hot water system would be appreciated.

SomeoneSomewhere

1804 posts

Uber Geek

Lifetime subscriber

#2669417 7-Mar-2021 12:17

'Hot water heat pump' normally refers to a 1-3kW self-contained hot water cylinder. They're pretty common and only a few grand.

You're looking for hydronic heating (i.e. using water to move the heat around). You probably need about 10-30kW of capacity, and the heat pump unit may or may not also include a bunch of extra stuff like pumps, expansion tanks, strainers etc.

Heat pumps are also substantially more efficient with lower water temperatures, so the systems tend to be designed to move more water at ~45C, instead of less water but around 60-70C like gas systems.You may not have enough capacity if you simply drop in a heat pump.

Jiriteach

1119 posts

Uber Geek

ID Verified

Lifetime subscriber

#2669423 7-Mar-2021 12:25

path:

Thanks @SomeoneSomewhere and @Jiriteach.

The system was designed by HeatIQ and installed by Carrington Plumbing. Heat source was a Vokera condensing boiler. The controls divert hot water from the boiler to the hot water cylinder or the underfloor manifold or the radiators based on thermostats upstairs (for radiator) and in each of the 7 zones for underfloor heating.

The actuators controlling the valves failed and the controls have been ineffective, and the boiler failed after 6 years and the plumber said it had to be replaced and was replaced. Since then the controls are totally defunct. Haven't found anyone who can fix this.

Can you provide any information on this Danfoss system?

Given this situation and the advances in hot water heat pump technology was wondering if that would more worthwhile investing in, with a view that possibly solar can provide some energy for the heat pump if I decide to have some PV panels as a next step?

Previous Geekzone comments in 2013-2016 have indicated that a hotwater heat pumps would be about $3.5k, whereas suppliers I talk to now talk about over12k to $20k. I would have expected prices of these would be coming down because it is a relatively new technology?

Any suggestions and advice re the controls and the heat pump hot water system would be appreciated.

Check out the Danfoss Link or Danfoss Ally systems - https://www.danfoss.com/en/products/smart-heating/dhs/smart-heating/?sort=default_sort
They are provided in NZ by Central Heating NZ - https://www.centralheating.co.nz/

I have Danfoss TRV wireless values on our radiators around the house. They communicate to the central controller which communicates to the boiler relay. Each valve can be set at its own temp and this will instruct the controller to fire the relay on to the boiler. Its an awesome system and I control/set schedules/radiators etc. all from their app or use Alexa to change temp if need.

-- opinions expressed by me are solely my own. ie - personal