Got Data? How much leaking electricity is there in HVAC systems?

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Permalink Reply by A. Tamasin Sterner on December 7, 2010 at 3:04pm

This is what I have from some of our Baseload auditing:
Compressor Crankcase Heater in AC: 40 W
Zone Dampers on Air Handler: 30 W
Thermostat transformer: 4W
And... of course the 't-stat fan setting set to "on" always' which can be:
Airhandler fans on 24/7 (@400-600W)
500W x 24 hours x 365 days x .001kW/W = 4,380 kWh/yr @$.16 = $701 per year

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Permalink Reply by Steve Waclo on December 8, 2010 at 7:19pm

Tamasin:

You are really making every opportunity to hammer home that "fan on" issue :-).

Regarding the math, I usually skip a term by going straight to 8760 hr/yr...sounds much more impressive :-). Anything multiplied by that number is a bunch :-)

And $0.16/kWh !! I'm crying the blues at $0.14 in NV!

Can not be said too often!

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Permalink Reply by Jonathan Beers on December 9, 2010 at 8:56am

Can't tell you anything about boilers, but I could look up measured data for my own ECM furnace if that helps. If memory serves it was on the order of 10 watts total. I believe Scott Pigg of the Energy Center of Wisconsin has data for furnaces, but probably not boilers - he might have published the furnace standby in his Home Energy Magazine article of Nov/Dec 2003.

You might try posting this question on "The Wall" at HeatingHelp.com. This is Dan Holohan's web site, and some experienced hydronic contractors often give prompt answers to questions.

Alan Meier sent me to the Australian Standby Power study linked here: http://standby.lbl.gov/docs.html several years ago, but I don't recall if boilers were measured. Great study because it measured a lot of hard-wired sleepers, as you called them.

If you find good data please publish it - inquiring geeks want to know!

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Permalink Reply by Mark Richardson on December 9, 2010 at 4:00pm

Upstate NY is coming in at $.17/kWh

Steve Waclo said:

Tamasin:

You are really making every opportunity to hammer home that "fan on" issue :-).

Regarding the math, I usually skip a term by going straight to 8760 hr/yr...sounds much more impressive :-). Anything multiplied by that number is a bunch :-)

And $0.16/kWh !! I'm crying the blues at $0.14 in NV!

Can not be said too often!

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Permalink Reply by Steve Waclo on December 9, 2010 at 4:23pm

Mark:

 

"Upstate NY is coming in at $.17/kWh"

Does the meter reader wear a Lone Range mask on his rounds :-)??

Spent the coldest winter ever in Corning back in 99-00 and noticed how the state seemed to load up utility bills with surcharges. Corning Glass was booming at the time, but pity folks who had to pay the heating costs when things declined there later.Understand CG is now coming back.

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Permalink Reply by Rich Brunco on December 9, 2010 at 5:30pm

The only electrical stand by losses I believe would be from the control transformer. If there is no call for heat.

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Permalink Reply by Mark Richardson on December 10, 2010 at 4:05am

Steve Waclo said:

Mark:

 

"Upstate NY is coming in at $.17/kWh"

Does the meter reader wear a Lone Range mask on his rounds :-)??

Spent the coldest winter ever in Corning back in 99-00 and noticed how the state seemed to load up utility bills with surcharges. Corning Glass was booming at the time, but pity folks who had to pay the heating costs when things declined there later.Understand CG is now coming back.

 

They wear a mask, but it ain't Lone Ranger or Robin Hood!

Actually just about HALF of the electric cost (I'm in Central Hudson territory) is fees and transmission charges. You 'only' pay about $.08-.09/kWh for the electricity, the rest is delivery.

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Permalink Reply by Evan Mills on December 17, 2010 at 1:19pm

Just got some measurements from one boiler.

 

Heating mode: 936W

Circ pump and air handler: 396

Circ pump only: 216W

Cooldown (internal fan): 120W

All "off": 3.6W

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Permalink Reply by Pascal Jünger on December 20, 2010 at 9:00pm

If it's leaking, while it certainly does affect efficiency, wouldn't this nevertheless already have been calculated?

If not, then a 14 seer pump is not a 14 seer.

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Permalink Reply by Bradford E. White on January 2, 2011 at 2:46pm

If I may chime in, the newer hydronic boilers, (Viessmann Vitodens 200 being one I have personally installed, but others as well), often do cause an unexpected electrical consumption jump -at least the first time you install one. In our case, the internal blower fan and internal circulator (an ECM based Grundfos just the same), drew over 130 Watts over our previous baseline. The heating efficiency was admirable and worth it, but we paid no mind to the electrical consumption until we got the bill. I installed a Kill-A-Watt meter at the power supply unit for a season and it recorded over 600 kWH for a ten month period. This does not include the secondary circulator for the heating loop. We average about 18 cents per kWH here in Boston, BTW.

These are net boiler numbers. Our first month was double this but we found the culprit: When the boiler fired it created the tell-tale condensing boiler plume. The plume in turn activated the IR/Motion Detector on our outdoor flood lights... live and learn.

Tamasin illustrates the much larger parasitic losses of moving air. All that mass of low specific heat vs. water, it is not an efficient delivery method. The Btu per Watt ratio is rather low.

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