variable speed pump

[mas985]

I think the highest tier in your area is $0.11/kwh. So assuming typical 2" plumbing, here is the running cost for a single turnover.

Typical 1.5 HP Pump: $17.43/month

Intelliflo running at 3144 RPM to match flow rate of 1.5 HP pump for the in-floor system full time: $15.62/month

Intelliflo at 1000 RPM when not running the in-floor system at all: $3.14/month

So worst case, your savings will be about $2/month which would take a long time to pay off the VS. At a cost of $900 for the pump, break even would be 450 months or over 37 years.

However, if you are able to split the run time with the in floor system and run 50% at 1000 RPM, your savings could be up to $8/month. With the same pump cost of around $900, break even would be around 112 months or a little over 9 years. Not great but maybe worth it.

Another option would be to replace your current motor with a two speed motor. At a cost of around $300, you would save about $5/month with running 50% at low speed but break even would be around 60 months or 5 years.

Note too that it would take over 16 years before the VS would become more cost effective than a two speed motor swap.

It really comes down to how much you will be running the in-floor system. They tend to be power hogs.

BTW, I forgot to ask how long you run your current pump?