Constant circulation vs increased electrical costs

Bill NTSG

What ever the cost is I don't really notice it in my electric bill. I had forced warm air and I was uncomfortable. Temperature swings, overdry sinus etc. I had hydro air and it was better. I then had forced hot water base board with on/off operation and it was a great improvement but....... I still had somewhat of a temp. swing and associated expansion/contraction noises.

Three years ago I went to outdoor reset and constant circulation. I have added an indoor sensor but have not conncted the wires yet. AT ANY COST, this is the most comfortable home I have ever been in. The temperature swings are completely eliminated, there are no drafts, no expansion / contraction noises, just comfort. This is the home I have lived in for the last 16 years so it is a very good comparison of the different systems. So if it cost you $100 a year to run the d#@! pump I would pay it. You are paying for COMFORT. It is hard to put a price tag on it if you have not experienced it.

All that aside , steady state is steady state. I do not wax eloquent here. I am not an engineer or have an education [yet] But I do know constant circ. is the right thing to do for several reasons. Warm is good, cold to hot back to cold is not my idea of the best thing

Kevin_10

Constant circulation vs increased electrical costs

Is this an issue? If so , what is a breakeven point for the increased cost for electricity being balanced by fuel savings? Thanks

Boilerpro_3

Yes it is an issue....

B&G has studied it,I believe, when looking at the effect on pump run time when starting to use outdoor reset, and on big buildings it can be significant dollars. I've done some basic calcs with the draw of a NRF-22,multiplied by the run time of the heating season and then the electric rate. You can figure roughtly 2KW per day for the little pumps or about 360 kw per year. AT 10C/kw thats $36.00 per year per pump. If you have lots of zones pumps this could really cost you alot of money.


Boilerpro

Al Letellier

constant circ

We're doing a job with 13 zones of radiant. It was suggested that we use constant circulation and I agree, but was concerned about operation cost. I'm not a fan of zone valves, but the system design is using one pump (with backup)and 13 normally open zone valves. The decrease in elecrtrical comsumption was quite dramatic.
There's always a better way as long as stubbornness doesn't cloud our vision, and I'm as stubborn a Frenchman as ther ever was!!!!!!!!!

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

heatboy

Isn't that too many........

ZVs to put on one pump? What is the total flow rate required for all of those zones? Depending on GPM requirements, I try to limit ZV to pump at 5. If done correctly, your system may be able to run three Grundfos 15-58 pumps set on first or second speed. Electrical consumption on speed one is around 36 watts on the 15-58. Three pumps would total less than 150 watts. Not much for all those zones. I have good luck with the Danfoss zone valve, so far.

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

Gary Fereday

on-off start-stop still-moving?

It takes a dead short across the line to start any motor. the power used in that instant is very high. Now as the motor moves up to speed, the water is slowly baginning to move, that takes power over a longer time. Just like an auto at speed constant controlled speed, the auto uses the least gas (except when in the garage. Constant proper flow pump operation is the best use of the pump. It'll last longer and cost less to operate. And like the post says "What cost COMFORT ?" JMHO bigugh

Kevin_10

Thanks for the practical reply. I do like comfort.

Al Letellier

too many zone valves

Good catch heatboy. There are actually two pumps on eleven radiant zones and one on a high temp zone. It's a Viessmann design and I have no doubts that it works.....

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

David Van Wickler_2

How many Zone Valves is too many?

?

I just designed a small 23,000 square foot home with 2 pumps (1 run/ one standby alternating) 1/2hp @ 42gpm and 60 feet of head with 17-1" zone valves with remote manifolds. Beat the competitors with this principle.

I've got in my back pocket flow limiting type valves (Griswold) that "push back" when a zone(s) close. Where does the water go? Variable speed pumping slows the pump down with an index delta P transducer mounted about 200 feet away a the end of the line.

The other guys designed a 17 pump system with 17-1" supplies and 17-1" returns. Even with Pex supply and return leaders, that's a lot of pipe running throughout the house.

17 pumps at 75 watts = 1275 watts


1 pump at 1/2hp = 380 watts
17 ZV's at 3watts = 51 watts
total 431 watts

energy savings my way - 50%

Installed cost my way - less than there way.

Look on the other guys face, priceless

DVW

hot_rod

It's not just

the amount of electrical energy consumed but more importantly the amount of work you get from the circ for the energy it consumes! IF the circ is running on the knee of it's curve a wet rotor circ is somewhere in the 20% electrical efficiency range. Rarely would a row of zone pumps ALL be operating at the "sweet spot" so efficiencies may drop to 10% or less.

By far the best bang for you electrical energy dollar would be zone valvs with a VS pump or second best a PAB to help keep a single speed pump running efficiently. Have a second pump piped in with isolation to minimize downtime should the primary pump fail on midnight Christmas eve

hot rod