How to heat water: Steam boiler or Heatpump

Olivejack

Last Spring we installed a heat pump to provide hot water during the non-heating months so we could turn our steam boiler completely off. Now that it is Fall and the boiler is running again, we are getting conflicting advise on how to heat our domestic water. One professional feels we should continue to use the heat pump for hot water and the boiler for heat, as each are most efficient doing the job they were designed for. The other professional feels that since the steam boiler has to maintain a certain temperature anyway, we might as well have it heat our water. We're confused. Any opinions? Thank you!

Spence

What kind of fuel do you have for your boiler, and what is the cost? What is the COP of your DHW and what is the cost per KwH? Answering these questions helps us determine the economy, yet doesn't address the ROI if you have to cough up some loot to add a DHW loop to your steam boiler.

Olivejack

I'm not real clear on the lingo but we already have a DHW loop which is what we used in the past. We use oil which runs about $3.50 right now and have a brand new Peerless boiler. The basement runs about 67 degrees with the boiler and heat pump running so it is not like the heat pump is out in the cold.
I assumed that if we were already making steam it was no big deal to make hot water as well, so I guess I'd like to know if running the boiler water through the hot water heater cuts down on the boiler's efficiency or makes it run more often. I appreciate all the comments even if seems it may be akin to "six of one or a half dozen of the other".

Spence

Since you didn't include the cost of your electric or the COP (efficiency) of your heat pump to compare costs, we don't know if the $15.00 you spend to take a shower is more or less than the heat pump DWH.