Electrical Usage Puzzle in Gardner, MA

[Potluck_Crew]

We need some creative minds. New owners of old home since July. We have Solar System that generates between 350 to 600 per month. We are on net metering through National Grid.

Our electrical/heating profile
Solar Panels Size: 5.04 kWdc, Monitoring Site: https://www.solrenview.com/SolrenView/mainFr.php?siteId=522
5 mini splits 15 years old
Appliances are mostly 10 years or older, so not as efficient.
Heat: Harman Accentra insert from 2008-we've tested it for electrical draw-pretty much as expected.
Oil Burner that runs both radiation steam heat and radiant heat. Both on programmable thermostats.

Sounds totally awesome right??
Things were moving along great in July, Aug, Sept, Oct .Total KWh usage of 10 to 50 per month(with the Net Metering). This translated to monthly bills of under $25.

Then in Nov/Dec...everything changed and it was huge. Our bill for Nov (which didn't arrive until Dec 20) showed 930 Kwh usage(Net). Then the next bill arrived with a 1500 Kwh(Net) usage.

We IMMEDIATELY shut down the mini splits, which we were already using sparingly, relying mostly on Pellet stove and some oil based heat.

Fast forward till late January, next bill showed 1000 Kwh usage.

We asked National Grid to come investigate if the net meter was working correctly. No finding.

We had a virtual Home Energy assessment with Mass Saves. Main finding was need for more insulation, which would not have increased the electrical usage except in oil burner and pellet stove use.

We purchased a Kill A Watt measuring device to test pellet stove as use was added in Nov.

The pellet stove may account for some KWh increase but not the huge one. Averaging a draw of between 120watts (lower settings) and 180watts (full power). We thought perhaps the igniter was stuck on, but not the case!

I report the Solar Generation each month to Mass CEC, so I know it is producing.


Where do we go from here? Any ideas on things we should check?

 

[begreen]

The big draw could be 220v loads. The clothes dryer and hot water heater are typical big consumers.

 

[mcdougy]

How is water supplied to the home? Is it a 220v pump and well or municipal water line? Is there circulating pumps involved in the heat system?

 

[Solarguy3500]

Do any of the rooms in the house have electric baseboard heaters?

 

[ABMax24]

Electric heat of any kind.

Baseboard heaters, portable heaters, space heaters, water tank heater, heat trace on water lines, heaters for animal waterers, electric infloor heat.

I'm assuming most of the load is from the mini-splits though.

 

[gthomas785]

Does your house have those roof heat cables that come on when it's below 30

 

[peakbagger]

Could you describe what the spreadsheet is showing ?. It looks to me like a solar production meter versus a household usage meter. Solar systems usually are fit to the house and in most cases the roof pitch is lower than optimal for year round total production. This usually means a shallower pitch and more production in the summer, but less total over a year. In some cases, the solar panels cover the total summer load of the house and spare power goes back to the utility to build up credit which is rapidly exhausted in the fall and winter.

I would help if you have a spreadsheet that shows solar production, surplus power to the utility and power purchased from the utility. On my Eversource bill its broken out a net sales and net purchases. BTW used electric power meters are cheap on Ebay, it is very handy to have on on your solar output if you do not have a production meter. In theory many PV systems have that available.

For completeness, (probably not applicable to you) Do you buy your power from the utility or a third party seller?. Yes you still would buy transmisssion services from the local utility but many states allow customers to buy from third parties. These third party sellers do not handle net metering well if at all and many have seen significant rate increases with the big run up in natural gas pricing. A general hint is do not look at dollars when tracking energy use, look at KW hours, then look at the total cost per KWhour delivered. and see how it changes over the year. Some local utilities have seasonal rates (similar to natural gas bills). Most seasonal rates for power are going to have significant run up this winter.

If it comes down to that you are just using a lot more power, the prior posts list quite a few potential energy hogs. If you were in the country, wells can develop leaks in the piping on the discharge of the pump can leak causing the pump to run near continuous. If the leak is in a well casing its not obvious.

Once you have gone through the usual suspects than its time to get a home energy monitor. I like CT (current transformer) based units but there are units that claim to be able to detect appliances with no CTs. I think they still need a CT on the solar output. They require less metering but one big caveat is that fitting a CT on the main incoming line to the service panel may be difficult (in my case, it would require major rewiring due to lack of physical space)

 

[SciGuy]

We need some creative minds. New owners of old home since July. We have Solar System that generates between 350 to 600 per month. We are on net metering through National Grid.

Our electrical/heating profile
Solar Panels Size: 5.04 kWdc, Monitoring Site: https://www.solrenview.com/SolrenView/mainFr.php?siteId=522
5 mini splits 15 years old
Appliances are mostly 10 years or older, so not as efficient.
Heat: Harman Accentra insert from 2008-we've tested it for electrical draw-pretty much as expected.
Oil Burner that runs both radiation steam heat and radiant heat. Both on programmable thermostats.

Sounds totally awesome right??
Things were moving along great in July, Aug, Sept, Oct .Total KWh usage of 10 to 50 per month(with the Net Metering). This translated to monthly bills of under $25.

Then in Nov/Dec...everything changed and it was huge. Our bill for Nov (which didn't arrive until Dec 20) showed 930 Kwh usage(Net). Then the next bill arrived with a 1500 Kwh(Net) usage.

We IMMEDIATELY shut down the mini splits, which we were already using sparingly, relying mostly on Pellet stove and some oil based heat.

Fast forward till late January, next bill showed 1000 Kwh usage.

We asked National Grid to come investigate if the net meter was working correctly. No finding.View attachment 291153

We had a virtual Home Energy assessment with Mass Saves. Main finding was need for more insulation, which would not have increased the electrical usage except in oil burner and pellet stove use.

We purchased a Kill A Watt measuring device to test pellet stove as use was added in Nov.

The pellet stove may account for some KWh increase but not the huge one. Averaging a draw of between 120watts (lower settings) and 180watts (full power). We thought perhaps the igniter was stuck on, but not the case!

I report the Solar Generation each month to Mass CEC, so I know it is producing.


Where do we go from here? Any ideas on things we should check?


View attachment 291154

Take a look at you electrical panel to see all the 220 breakers. In the cabin I live in there's a base board heater in the arctic entry as well as a crawl space heater that come on in the winter when it gets cold that really boost the electric bill. Since their space isn't shared with the pellet stove, we're paying a premium heating them during the cold months.

Hugh

 

[velvetfoot]

Radiant heat? Like hot waterwith a constantly running pump? How do you do Steam and Water from the same boiler?
For what it's worth, you can get more efficient pumps (ecm) or ecms that adjust throughput automatically...I think. lol.

 

[Potluck_Crew]

How is water supplied to the home? Is it a 220v pump and well or municipal water line? Is there circulating pumps involved in the heat system?

The water is municipal. The Heating system, part is radiant heat. Other is steam radiators. Both from same oil boiler.

 

[gthomas785]

Radiant heat? Like hot waterwith a constantly running pump? How do you do Steam and Water from the same boiler?
For what it's worth, you can get more efficient pumps (ecm) or ecms that adjust throughput automatically...I think. lol.

It's been done alot, you run a boiling water loop off the boiler through a HX then to a mixing valve for the radiant. Hot start /low limit on the boiler keeps that water hot when steam isn't calling.

 

[stoveliker]

It's been done alot, you run a boiling water loop off the boiler through a HX then to a mixing valve for the radiant. Hot start /low limit on the boiler keeps that water hot when steam isn't calling.

my espresso machine does it too...

 

[EbS-P]

My utility installed smart meters. And now I have a free hub that interfaces with the meter and I can measure real-time power consumption. It’s pretty handy. I can turn an appliance off or a a breaker (just no the one one with my hub and WiFi router) and see the change.

This was todays and the spikes are where the heatpump goes into defrost and kicks on 10kw heater.

 

[Potluck_Crew]

Could you describe what the spreadsheet is showing ?. It looks to me like a solar production meter versus a household usage meter. Solar systems usually are fit to the house and in most cases the roof pitch is lower than optimal for year round total production. This usually means a shallower pitch and more production in the summer, but less total over a year. In some cases, the solar panels cover the total summer load of the house and spare power goes back to the utility to build up credit which is rapidly exhausted in the fall and winter.

I would help if you have a spreadsheet that shows solar production, surplus power to the utility and power purchased from the utility. On my Eversource bill its broken out a net sales and net purchases. BTW used electric power meters are cheap on Ebay, it is very handy to have on on your solar output if you do not have a production meter. In theory many PV systems have that available.

For completeness, (probably not applicable to you) Do you buy your power from the utility or a third party seller?. Yes you still would buy transmisssion services from the local utility but many states allow customers to buy from third parties. These third party sellers do not handle net metering well if at all and many have seen significant rate increases with the big run up in natural gas pricing. A general hint is do not look at dollars when tracking energy use, look at KW hours, then look at the total cost per KWhour delivered. and see how it changes over the year. Some local utilities have seasonal rates (similar to natural gas bills). Most seasonal rates for power are going to have significant run up this winter.

If it comes down to that you are just using a lot more power, the prior posts list quite a few potential energy hogs. If you were in the country, wells can develop leaks in the piping on the discharge of the pump can leak causing the pump to run near continuous. If the leak is in a well casing its not obvious.

Once you have gone through the usual suspects than its time to get a home energy monitor. I like CT (current transformer) based units but there are units that claim to be able to detect appliances with no CTs. I think they still need a CT on the solar output. They require less metering but one big caveat is that fitting a CT on the main incoming line to the service panel may be difficult (in my case, it would require major rewiring due to lack of physical space)

Water is municipal supply so no well or 220V draw there.

The spreadsheet is showing the solar generation only. We only have results of net metering with our National Grid system so getting a record of what is sent back out into the electrical grid is not possible. That is a major frustration of mine!

I do have a production meter with the solar system. That basically is what when into the spreadsheet by online entry. It seems to match what the Solrenview site is recording. We had NO credits built up in the summer, always some sort of Plus on net metering.

I am looking at the KWh monthly that National Grid reports via our net meter.

I attempted to create a spreadsheet by calculations.

 

[Potluck_Crew]

Do any of the rooms in the house have electric baseboard heaters?

no electric baseboards.

 

[Potluck_Crew]

Does your house have those roof heat cables that come on when it's below 30

That I do not know.

 

[Brian26]

Emporia just released the Vue 2 for $150 that can monitor 16 circuits. This would show you exactly where your energy use is. I only got around to installing it on my main larger loads. You can also monitor your solar with the unit if it's feed into your main panel.

 

[gthomas785]

That I do not know.

They usually look like this or similar.

 

[Potluck_Crew]

No. Thanks!

 

[Highbeam]

They usually look like this or similar.

OMG, they just run a screws through the roofing?

 

[gthomas785]

OMG, they just run a screws through the roofing?

Apparently that installer did. The most common ones I've seen just clip onto the bottom edge of the shingle.

 

[RockyMtnGriz]

I'm multitasking, so if I list something you've already tried, forgive me for not reading carefully, but here's the low tech, non-spreadsheet, non-smartphone approach I'd use first in investigating the issue:

There are some metal roof valleys, and some entire metal roofs that are heated in a way that would not be visible from the exterior. They're normally thermostatically controlled and could use a ton of power once the weather gets cold. If you have thermostatically controlled heating tapes on your plumbing, that could also be the culprit. Heated downspouts and drain lines are included possibilities here.

It looks like you have an old style rotating dial meter. Those make it pretty easy to watch the usage change as you turn breakers on and off. I'd account for what any breaker that causes the meter to spin significantly in cold weather is doing with the power, starting with the 220v breakers. This would be best done at night when your solar is offline. Alternatively, turn off all of the breakers, and just turn one on at a time, maybe with the obvious big loads like the fridge, water heater, heat sources turned off or unplugged at the unit. You can measure most of those with your watt meter at the unit to know what they're up to.

I'd wonder what the mini-splits are doing. Could they be doing frequent power sucking defrosts? Could they be going into a backup resistance heat mode?

Slim chance, but I wonder about the hybrid HWH. The water temp coming into my house varies a lot seasonally, dropping to near freezing at mid-winter. Could colder water coming in be causing the HWH to kick into resistance mode frequently? I think that can be programmed out to test. I know my water heating load also goes up a lot in the winter, both because of cold inlet temperature, and because of the tendency to prefer warmed water when it's cold. Plus, anything mixing hot and cold for a desired temp (shower, washing machine) is going to need more hot and less cold for the same temp.

The thing about a hybrid HWH, is if it's using inside air, not only will the unit use power, but you're going to need some form of heat to replace what it's taking from the home, so you have to pay for the heat one way or the other in the winter. I would expect that to create a significant difference season to season all by itself. They're a good idea, that makes far more sense in the South, than the North.

Is your house lit up like a sports field inside and out during the long dark days of winter? Some I see I would need sunglasses to live in!

Have your kids secretly taken up cryptomining as a winter hobby?

Good watt hunting!

 

[DBoon]

A 5 kW array in the northeast is is likely to generate, on average the energy a typical household generates in an average month. In MA, probably about 5.5 to 6 MWh/year.

I can easily see heat requirements via mini-splits or heat pumps for a 2000 square foot house running at 500 kWh in November and 1000 kWh (or more) in January. Add in electric hot water (colder input water means more electric usage to heat it, or use of electric resistance means to heat it instead of the heat pump on the water heater) and it is easy to see how your electric usage could go up a lot in the wintertime.

 

[stoveliker]

If your heat pump water heater has a setting that you can switch off the resistance back up heat (that most have), I'd do that and see what that does to your kWh consumption.

 

[Rusty18]

My heat pump hot water tank can be selected hp, hybrid, or resistance. It made a $80 jump in the electric bill when I changed it from hp only to hybrid...it got changed back!