Infloor Hydronic Floor Heating in winter

[06Honda]

I have a one level home on slab with infloor hydronic heating via a hot water tank run on natural gas. There is 2 zones in the 1080 square foot home and it works great. My question is we have an HRV that we don't run year round (summer is too hot for that) but will turn it on in winter from time to time when the air gets a bit dry or windows show some moisture on them from cooking etc. Is it a good idea to set the HRV at say 40% humidity and just let it run 24/7 during the winter season instead of turning it on when we feel it is needed. The air that comes in isn't cold but coolish so I am assuming this is normal as it gets warmed up slighty in the unit prior to coming in and aids in overall heating costs. Can't seem to wrap my head around how this reduces heating costs but does help for sure with humidity levels.

 

[Sparky617]

I'd think a HRV would cause an increase in heating costs but it does recover heat unlike opening a window to get fresh air.