Efficient DHW plan for a soaking tub? - GreenBuildingAdvisor
Summary
The article discusses an efficient domestic hot water (DHW) plan for a soaking tub, exploring options for water heating and distribution while considering space and efficiency constraints.
Why It Matters
Understanding efficient DHW systems is crucial for homeowners and builders aiming to reduce energy consumption and manage water heating effectively, especially in regions with hard water. This discussion highlights practical solutions and considerations for optimizing water heating systems in residential settings.
Key Takeaways
- Consider the capacity and material of water tanks when planning DHW systems.
- Evaluate the efficiency of electric tankless options versus traditional tanks.
- Space constraints can significantly influence the choice of water heating solutions.
Efficient DHW plan for a soaking tub? AdamPNW | Posted in General Questions on February 24, 2026 08:29pm Hi all, My efficient DHW plan involves:1) a sanco 2 heat-pump water heater2) a compact, insulated, home-run distribution3) low-flow fixtures… …except for a soaking tub! I’ll be building it myself to fit the space, I’m estimating ~100-120 gallons, with a 1/2” tub filler fixture. I had initially planned to install the 119 gallon tank (first hour rating 135), but learning that this tank is not stainless steel, and we have hard water. The 83 gallon (first hour rating 115) is stainless steel. As far as I can tell, the first hour rating accounts for the additional volume of water heated during use, but NOT the additional volume from a mixing valve. Since the sanco tank produces 150 deg water I’m guessing this will add a significant amount, but not sure if it will be enough to fill a 120 gallon tub. So, one option is to add a small electric tankless for just the tub (all electric house so no gas), but this will probably be inefficient, although I do have space for it. another option is to add a second 83g tank, but don’t have the space for that, and it seems overkill. Are there other options I’m not aware of? thanks!! Answer GBA Detail Library A collection of one thousand construction details organized by climate and house part Search and download construction details Join the leading community of building science experts Become a GBA Prime member and get instant acces...
