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· Registered
1 Posts
Discussion Starter · #1 ·

I moved into a new house this week, and I'm currently waiting on the manual for the heating system, which seems far more complex than any heating system I've used before :)

I've tried searching online for some information but it's hard to find any relevant information or guides.

I would really appreciate if someone could help with the following, thanks.

01 - Is an 'Air to Water' more cost efficient to run than a regular heating system?

02 - Should it be always running, or best to set it on timers (from what I understand it is constantly running and just keeps the temperature steady at all times?)

03 - Based on the short video i've created below, has anyone ever come across this system / setup? Every room has a thermostat, but when I try increase the temperature it changes from SET to RT and then it seems like it takes a couple of days to climb to the temperature, so i'm completely lost with it.

Thank you in advance for your help.

· In Loving Memory
42,671 Posts
RT is the room temp.

Looks like you have a radiant heat system. They are not designed to give a fast temp increase. They're more a set it and forget it system.

If you were to use timers, then you wouldn't be able to maintain room temp. Leave it run as it deems it needs to.

· Registered
4,168 Posts
Our house also has an air-to-water heat pump and I’ll agree that it is a more complex system than any that I’ve used before.

If you have more questions can you give us another video that pans slowly up and down in the piping enclosure and a better view of the unit control panel and tell us a bit about the house and heating system (how many floors, what climate it is located in, model number for the Ecodan, are there any other heating/cooling systems, etc). I can see four red indicators (warm supply) and four blue indicators (cool return) going into the floor, so it looks like at least part of the heating is done by four in-floor pipe loops. The Ecodan system can also be used to produce DHW (domestic hot water), but I can’t get a good enough view of the piping to see if that is part of your system. It does appear on the control panel, but with a “standby” icon beside it, so I’ll guess that it is not installed as part of your system.

Question #1 – that depends on what you mean by a “regular heating system”. One of our federal government departments has done a good explanation of the pros and cons of heat pumps. This link has sections discussing the efficiency and energy savings that can be achieved by using them. A comparison to other heating systems depends on the cost of natural gas, heating oil and electricity where you live. Presumably somebody has done that already and that’s why it has been installed in your house. Generally speaking, heat pumps are a good alternative for locations with mild winters. You’re already paying the higher up-front capital cost of the system and, if the right choice of system was made, you should reap the lower operating costs over coming years.

Q2- In-floor radiant heating is one of the most comfortable forms of house heating that there is. One of its downsides, though, is “thermal lag” caused by the thermal mass of the floor. The in-floor tubes are heating the floor, then the floor radiates that heat into the room. As beenthere has indicated, trying to change the room setpoint for different times of day isn’t really practical. We leave ours the same all the time. To give an idea about the effect of thermal mass, the lower story of our house has the heating tubes in a four-inch thick concrete slab. When there is a winter storm and the power goes out it takes 12 hours before the room temperature drops more than a single degree.

Q3 – Yes, this is the “thermal lag”.

If you’re technically minded, there is a lot to learn about your system which might pay off down the road. For example, Mitsubishi probably specifies a minimum pressure in the water circulating loop system. If that is what the gauge in your video that we get a short glimpse of is showing, there’s a good chance that it’s below the minimum.

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