This month's Home Power has an article by John Siegnthaler regarding the use of air to water minisplits for heating in place of a standard air to air minisplit. Home Power currently limits access to their articles to subscribers so I cant post a viable link. This may change at some point as they just published their last issue.
He makes some very convincing arguments that for heating, an air to water unit combined with low temperature emitters is a better fit for heating and I tend to agree with him. My air to air minisplit is installed to manufacturers specs but I find that the placement is optimized for cooling. In heating mode it does tend to stratify the air in the room more then radiant baseboard would. It throws the heat into the center of the room while the heat loss is in the walls and windows. The heat is also moved by air and that does cause drafts which for most folks mean they want to turn the thermostat higher. Of course using this approach for cooling would be a disaster for most as moisture would collect on the emitters. This means the big advantage of all in one solution for heating and cooling that is somewhat solved by a minisplit doesnt apply to an air to water so a separate cooling only air handler is needed. It wouldn't take much to put in some two way valves on the glycol lines but it would be extra equipment and piping.
The big advantage to air to water is no need to hire a tech to purge and charge the lines. All the refrigerant stays outside in the outdoor unit and the only plumbing needed is glycol. This means the potential for DIY install is much easier and I expect the potential for refrigerant leaks is less. Tom in Maine on this site sells one brand but I believe he stated he went through a few brands before he found one that he could depend on.
The scary part to me is the list of manufacturers of air to water minisplits are all unknowns. Aermec,Chiltrix, Maritime Geothermal, Space Pak and ThermAtlantic Energy Products were all mentioned in the article but are not household names to me. I am curious if there is just one chinese company that makes them and just badge them for different firms.?
I dont plan to replace my air to air unit as I mostly use if in shoulder seasons until its worth running the boiler but if someone were starting from scratch it may be worth considering.
He makes some very convincing arguments that for heating, an air to water unit combined with low temperature emitters is a better fit for heating and I tend to agree with him. My air to air minisplit is installed to manufacturers specs but I find that the placement is optimized for cooling. In heating mode it does tend to stratify the air in the room more then radiant baseboard would. It throws the heat into the center of the room while the heat loss is in the walls and windows. The heat is also moved by air and that does cause drafts which for most folks mean they want to turn the thermostat higher. Of course using this approach for cooling would be a disaster for most as moisture would collect on the emitters. This means the big advantage of all in one solution for heating and cooling that is somewhat solved by a minisplit doesnt apply to an air to water so a separate cooling only air handler is needed. It wouldn't take much to put in some two way valves on the glycol lines but it would be extra equipment and piping.
The big advantage to air to water is no need to hire a tech to purge and charge the lines. All the refrigerant stays outside in the outdoor unit and the only plumbing needed is glycol. This means the potential for DIY install is much easier and I expect the potential for refrigerant leaks is less. Tom in Maine on this site sells one brand but I believe he stated he went through a few brands before he found one that he could depend on.
The scary part to me is the list of manufacturers of air to water minisplits are all unknowns. Aermec,Chiltrix, Maritime Geothermal, Space Pak and ThermAtlantic Energy Products were all mentioned in the article but are not household names to me. I am curious if there is just one chinese company that makes them and just badge them for different firms.?
I dont plan to replace my air to air unit as I mostly use if in shoulder seasons until its worth running the boiler but if someone were starting from scratch it may be worth considering.
