I am converting a barn to a house, planning in hydronic in-floor heating. What are advantages and disadvantages of open and closed systems? I am planning on having solar as a pre-heat for the water, but know living in Canada doing exclusively solar would be a challenge, but as a pre heat would work. Second question: to heat the water for both domestic hot water and in-floor heating, to do propane of electric? The cost of both have gone up but propane is significantly up....

"Open" hydronic heating system? Too silly to discuss. See what Mr. Bean says about it:http://www.healthyheating.com/water_heaters_as_boilers.htm#.U2WKVvldXSg

Solar pre-heat? In the summer and maybe shoulder months. I would rather drive my pumps with a PV panel.

You could use an electric boiler and a Marathon water heater, this is what I do and the bulk of our business, both design and installation, is gas and solid fuel based.

And don't forget the air-to-air heat pump will operate for a third of the direct-resistant heaters.

Thanx for the reply. I am trying to stay away from ductwork in the barn, so an air-sourced heat pump is out. I will do ductless mini-splits for cooling the bedrooms in the summer. I switched to an on demand propane water heater about 6 years ago and love it, so I guess 2 systems will be needed for in-floor and DHW. I thought solar "pre-heat" even in the winter, if I can take the well water from 50 to even 80 or so, my water heater won't have to work as hard. Heating it enough in the summer months would be bonus. Would you drive the circulating pump for the solar panels by PV? Is that what you are getting at?

First, design - or redesign - your envelope with Passive House principles of 1) Thermal envelope, 2) air tightness, 3) insulation and windows, 4) minimizing thermal bridging. Utilizing exact PH levels of insulation are not as critical as paying good attention to the basic principles to end up with a home that works well. Once you have the envelope properly designed, heating and related energy usage become much, much simpler.

I heard recently from a Mitsubishi rep that possible by the end of the year they'll be coming out with a air source minisplit heat pump where the refrigerant line from the compressor will pass through a hot water heater on it's way to the indoor minisplit unit; in the process providing hot water.

Posted By Bob I on 04 May 2014 09:11 AM
I heard recently from a Mitsubishi rep that possible by the end of the year they'll be coming out with a air source minisplit heat pump where the refrigerant line from the compressor will pass through a hot water heater on it's way to the indoor minisplit unit; in the process providing hot water.

I want one!

"I heard recently from a Mitsubishi rep that possible by the end of the year they'll be coming out with a air source minisplit heat pump where the refrigerant line from the compressor will pass through a hot water heater on it's way to the indoor minisplit unit;"

It's called a de-superheater. Currently available as an aftermarket add on for conventional systems, it is all but standard on geothermal heat pumps.

The air source heat pump mentioned......there is such a thing as air to water heate pumps, there are also water to water heat pumps. First thing is to design the lowest possible water temperature requirement with good tube frequency. That will make whatever heat plant you use most efficient.

Joe, you really must feel passionate about this having posted in triplicate…LOL. Yes, we fully agree that this “technology” has been around for quite a while and that creating a well-insulated/well-sealed building envelope so as to be able to use the lowest HR floor hydronic fluid supply temp possible will maximize your heating system efficiency for a given heat source.

seems someone edited for me RB, I had no idea it was multiposted. Hopefully this only posts once.