Open loop radiant system, thoughts?

[Flexia]

I have been looking at options for my 26x40 garage for heat and also to have heated water for a hose hookup when washing cars in the winter. I do wash my cars about twice a week so it wouldn't go unused for periods of time.

To me the open system seems simple and easy and cost effective. But have heard things about Legionella growth. And for me it doesnt seem logical to add a heat exchanger and a 2nd pump just to have warm hose water. Is it really that bad to have a open system for one hose hookup?

My building is relatively small and the heat loose is around 17k btu and it doest make since to get a combi boiler either because of how little btu I will be needing.

What are your guys thoughts on this? And please dont make this a discussion on how Legionella can be in the system. I understand all that.

 

[Clik]

Legionella dies at temps above 140 degrees.

 

[Rookie2]

they make a mixing (called a tempering valve) valve just for that.

 

[Randy in Maine]

I have nothing to add but I also ran hot and cold water via 3/4" pex tubing to my garage for garden hoses silcocks (fed off my house on demand boiler about 30' away) and it is really a nice handy feature. I shut mine off in the winter via a shutoff in the garage plumbing wall (that also deals with the radiant floor heat manifold).

I runa closed loop heating system though and just ran the two 3/4" pex for hot and cold in the same underground conduits.