Where to start looking for Energy Savings

[sloeffle]

A few years ago the electric coop came around and installed smart meters. I noticed last month that the email for my electric bill was different than before. So I opened up the link on the email and now it goes to a new web site where I can see the my electricity usage from month-month etc.

They also have an app on that you can download for your smart phone. I downloaded the app and now I can see my electricity usage for the previous day. You can also look at your weekly trends.

In my mind I have been keep tracking of days we have been home a lot and days we haven't. And the days we do laundry and run the oven. I then go back and look at my phone and think about how we could use so much electric for hardly doing anything some days.

The house is all electric.

• Geothermal Heating and Cooling ( 22A, 4 ton Waterfurnace 5 series )
• House is set to 70F in the winter and 76F in the summer
• Marathon Hot Water Heater ( 4500W )
• Hot water is set to 120F
• 1.5GPM Shower Heads
• LED and CFL lighting. The lights that are used the most have been converted to LED.
• 2 adults, 1 child
• House is about 10 years old with good insulation and windows
• City Water. We have a well for outside yard hydrants
• 250W Stock Tank heater is used approximately 12 hours a day in the winter along with 100W chicken water heater. 350W x 12hours = 4200W
• Energy Star refrigerators. Stand Up freezer is not Energy Star
• Energy Star washing machine. Dryer is not
• We run a Energy Star dehumidifier in the basement during the summer
• Wife and kid have been trained to turn off lights after leaving a room.

Here are a couple graphs showing our monthly and yearly usage:





As you can see in the beginning of September we were on vacation. My phone shows the graph a little better but my base line usage is around 7kw/h a day. That seems reasonable to me.The last day of October we were not even home most of the day and we used around 40kw/h of electric. That is almost 2000 watts of electric being used per hour. I bought a Kill A Watt tonight and was looking at Efergy's also. My gut tells me it is my hot water heater.

My electricity usage seems to be a lot higher than what most folks on the board usually say they use. My neighbor generally uses over 2000kw/h per month but he has more occupants and his house is lit up 24/7.

Thanks,

Scott

 

[Circus]

I bought a Kill A Watt tonight and was looking at Efergy's also. My gut tells me it is my hot water heater.

Not bad, considering electricity is your only utility bill. Good thing about electric water heaters are they don't use much energy unless you use a lot of hot water. So you can save without changing any appliances. Same go's for the dehumidifier (all dehumidifiers are energy hogs).

 

[maple1]

https://www.hearth.com/talk/threads/monitoring-electricity-use.121772/page-8#post-1732051

I would suspect the dehumdifier firstly.

How old is the Marathon? We have an 80 gallon electric hot water heater - newer, but run of the mill. It can keep us (family of 5) in hot water in the summer months for around $30/mo, at 0.18/kwh. Conventional hot water heaters aren't as bad as some think (myself included until I got one & watched it). But if you run a dehumidifier a lot, a HPWH would pay double dividends as it dehumidifies while heating water.

 

[woodgeek]

18 MWh/yr is not so bad for an all electric house in a Midwest climate, IMO.

For the record, I am at 17.9 MWh/yr, but I have a more mild climate, an ASHP rather than a geo, and an EV doing 10,000 mi/yr.

Your analysis is correct...your biggest opportunity for saving is a HPWH and ditching the Marathon. Will save you ~2 MWh/yr directly. With a geo, the heat stealing will not be a big factor, your space heat BTUs are cheap. If it reduces your dehumidifer usage too, it might save you another 1-2 MWh/yr.

Even Energy Star dehumidifers are hogs, the energy star label just says it uses at least 20% less than the ones without the label. 80% of a hog is still a hog.

Another alternative is to dig into the basement dehumidifier need. If the basement is airsealed and insulated and not having bulk water intrusion, it should not need much dehumidification...and a branch of a central AC will usually keep it dry efficiently (if you have CAC). If you do have bulk water intrusion....you should address that for many reasons. If the basement is dry except for summer humid periods, you might get a nice benefit from airsealing your rims, which is easy if they are exposed. If they are finished, densepack cellulosing the joist bay adjacent and parallel to the rim can effectively airseal it (but you only get 2 out of 4 sides of the house) and is pretty cheap.

Other than reducing dryer usage, i.e. a clothesline in the basement (except in the summer), and chasing some phantom loads (track your fridge usage with a killawatt), there is not much to do.

The cheap geo BTUs will hurt payback on envelope/heating load improvements, but you could undertake them anyways, if you wanted. You can prob get a guy to do a simple blower door for <$100, and see if there is anything worth doing. You wont save a bundle due to the cheap BTUs, but you will get a more comfortable, quieter and better indoor air quality house, and could justify the cost of the work on those intangibles.

You did not say if the washer was 'HE', that is if it spins the clothes super fast to the point they leave the washer just 'damp'. This makes the clothesline option a LOT easier and drops your dryer usage a lot at any rate. For the dryer, just make sure it has a working 'dryness sensor' so it stops when the clothes are dry.

 

[peakbagger]

The stock tank heaters can burn up a lot of juice, someone I knew had one for her horse tank and it didnt have a thermostat. It just ran all the time, even with one with thermostat, the tank is open to the sky so in cold weather its heating the outdoors. I have seen some concepts where the tank is fitted with foam cover that reduces the opening. One of the horse was skittish and couldnt deal with that type if arrangement.

 

[sloeffle]

How old is the Marathon?

The Marathon is from 2012. It is a 50 gallon model. I did have a element go bad shortly after we go it. They replaced it for free but I have always had a suspicion in my mind of "what else is wrong with it".

I would suspect the dehumdifier firstly.

Dehumidifier is approximately 15 years old. That will probably be the first thing that I am going to hook my Kill A Watt meter up to. I try to only run the dehumidifier at night on low setting and when the AC is off. Basement is only 768 sq ft.

 

[sloeffle]

Your analysis is correct...your biggest opportunity for saving is a HPWH and ditching the Marathon. Will save you ~2 MWh/yr directly. With a geo, the heat stealing will not be a big factor, your space heat BTUs are cheap. If it reduces your dehumidifer usage too, it might save you another 1-2 MWh/yr.

I talked to Tom in Maine about buying one of his overstock Geysers. Our geo has a desuperheater that is hooked into our hot water tank so hooking up a Geyser might be a little tricky. I however only run the desuperheater during the summer since it robs heat away from the loop during heating. It might be worth looking into a setup that only runs the Geyser when the desuperheater is not running.

Another alternative is to dig into the basement dehumidifier need. If the basement is airsealed and insulated and not having bulk water intrusion, it should not need much dehumidification...and a branch of a central AC will usually keep it dry efficiently (if you have CAC). If you do have bulk water intrusion....you should address that for many reasons. If the basement is dry except for summer humid periods, you might get a nice benefit from airsealing your rims, which is easy if they are exposed. If they are finished, densepack cellulosing the joist bay adjacent and parallel to the rim can effectively airseal it (but you only get 2 out of 4 sides of the house) and is pretty cheap.

The basement walls are insulated on the outside with sheets of R-10 insulation. The basement walls were also sealed on the outside and inside. The rim joist / sill plate down to the 2nd block have been sealed with approximately 2" of closed cell foam. Our bedroom was getting too hot in the winter so I unhooked one of the duct runs and have it dumping into the basement now. This does seem to help dehumidify the basement when the AC is running.

You can prob get a guy to do a simple blower door for <$100,

Our electric coop will do a blower door test for 25$. I talked to the coop's "energy expert" last year and he told me that since the majority of my house sits on a crawl space it would be a waste of money. I probably should push him more on the subject. The bottom of the house over the crawl space is insulated to R-13 and covered with plastic.

You did not say if the washer was 'HE', that is if it spins the clothes super fast to the point they leave the washer just 'damp'. This makes the clothesline option a LOT easier and drops your dryer usage a lot at any rate. For the dryer, just make sure it has a working 'dryness sensor' so it stops when the clothes are dry.

Washer is a HE model. Good point about the dryer sensor. Anyway to check if it still good ?

Thanks,

Scott

 

[semipro]

I talked to the coop's "energy expert" last year and he told me that since the majority of my house sits on a crawl space it would be a waste of money. I probably should push him more on the subject.

I don't understand what having a crawl space has to do with whether a blower door test is helpful or not.

 

[woodgeek]

If it is an open crawlspace, he could be saying that it will leak like a sieve.

While the insulation and plastic sounds good under the crawl, if the plastic is not taped carefully, it can still leak like a sieve.

With blower doors, it is possible to block off interior doorways (and say, gaps under them) temporarily to partially isolate where the leaks are coming from. Many pros don't want to do this.....they would prefer a 'one and done' measurement...but a cooperative blower pro might be happy to do a little sleuthing with you.

 

[woodgeek]

I talked to Tom in Maine about buying one of his overstock Geysers. Our geo has a desuperheater that is hooked into our hot water tank so hooking up a Geyser might be a little tricky. I however only run the desuperheater during the summer since it robs heat away from the loop during heating. It might be worth looking into a setup that only runs the Geyser when the desuperheater is not running.

I was wondering. I would say that the difference in operating costs of a 12 season desuperheater, a standalone HPWH and a geyser on the Marathon are small enough to be in the weeds. If you don't want to run the DSH in the winter for any reason, then you should still get a geyser or a stand alone HPWH...

I would not even bother with combining it with the DSH to switch over in the summer. It might have a higher COP (**free hot water**) than a HPWH, but it won't dehumidify your basement, so the HPWH might actually use less energy than the DSH+dehumidifier. At any rate the theoretical difference is likely in the tens of dollars per year range...not worth expense of the additional plumbing work IMO.

With HP heating and low flow shower heads and modern appliances, the amount of $$ that goes into DHW is so small as to not really justify overly complicated solutions or small tweaks.

If you have the marathon already, I think the case can be made to do the geyser hookup, esp if you can get one cheap and do it DIY. And retire the DSH in the process. In an insulated basement, the cooling effect of the HPWH will be reflected in lower summer AC, and the BTUS it collects in the winter will come from the geo anyway.

 

[semipro]

If it is an open crawlspace, he could be saying that it will leak like a sieve.

While the insulation and plastic sounds good under the crawl, if the plastic is not taped carefully, it can still leak like a sieve.

With blower doors, it is possible to block off interior doorways (and say, gaps under them) temporarily to partially isolate where the leaks are coming from. Many pros don't want to do this.....they would prefer a 'one and done' measurement...but a cooperative blower pro might be happy to do a little sleuthing with you.

Agreed on all points.
However, a poorly sealed floor would be one of the easier leaks to address when compared to walls and roof. It seems to me that making gross assumptions or saying "you don't want to know" is just irresponsible and unhelpful.

 

[sesmith]

I think if you put a kill-a -watt meter on your stock tank for a few days, you'll be amazed at how much of an energy hog it is. Here's a link to my solution:

http://www.builditsolar.com/Projects/WaterHeating/InsulatedStockTank/InsulatedStockTank.htm

It saved a lot of electricity. We only had 2 or 3 horses, at the time, so the reduced capacity wasn't a problem. There are also several ideas for a solar heated stock tank, as well, on Gary's Build it Solar site.

 

[sloeffle]

If it is an open crawlspace, he could be saying that it will leak like a sieve.
While the insulation and plastic sounds good under the crawl, if the plastic is not taped carefully, it can still leak like a sieve.

It is a vented crawl space. There are some holes in the plastic from when I had to replace the floor in my kitchen due to pin hole leaks in the pex piping caused the floor to rot out. I definitely need to get the plastic sealed back up before winter. Crawling around a 3 foot tall crawl space is not my idea of fun.

When the spray foam guy was out I asked him about sealing it up. He gave me an estimate of 2800$. I don't think the pay back is there to justify the cost.

 

[woodgeek]

I'd prob cover the hole and tape the easy seams in the plastic (with appropriate tape) before doing a blower door.

 

[sloeffle]

I think if you put a kill-a -watt meter on your stock tank for a few days, you'll be amazed at how much of an energy hog it is.

250W is the smallest heater that I can use for my stock tank in our climate zone. I saw some that were 1500W . I have a timer on it so it only runs 30 minutes every hour. During the middle of the polar vortex I did have to run it 24/7 since the water was icing over very fast. I put a couple straw bales on the prevailing wind side and it did help.

Thanks for the link to the plan. I will have to check them out.

 

[STIHLY DAN]

Cable boxes especially older ones cost as much to run as a freezer.

 

[begreen]

250W is the smallest heater that I can use for my stock tank in our climate zone. I saw some that were 1500W . I have a timer on it so it only runs 30 minutes every hour. During the middle of the polar vortex I did have to run it 24/7 since the water was icing over very fast. I put a couple straw bales on the prevailing wind side and it did help.

Thanks for the link to the plan. I will have to check them out.

An insulated tank will help. Also, looks like the summer load is higher. Lighting, heating loads should be lower so I am going to assume this is AC. If so, insulate and seal the ducts better and maybe consider a more efficient setup or plant some large shade trees near the house.

 

[sloeffle]

Nyletherm has been ordered. By the estimates that woodgeek gave me ( 2.2MWh/yr * .16kw/h ) it should pay for itself in about a year.

 

[sesmith]

Nyletherm has been ordered. By the estimates that woodgeek gave me ( 2.2MWh/yr * .16kw/h ) it should pay for itself in about a year.

That's $352 per year, so you either found a real deal or are maybe off by a decimal point?

I'm not sure I totally agree with his optimism but here's why. I used the #s for my house and GSHP with desuperheater and plugged in your electric prices (.16/Kwh), and here's what I came up with based on my 10.6 MBtu water heating requirement per year.

With a standard electric water heater alone, that water heating would cost approx. $507.

With my desuperheater and estimated desuperheater efficiency of 4.33 COP, and the DSH supplying about 58% of my hot water over a year, that cost for water heating would be approx. $280 (fwiw, the COP rating I used came from the engineer who designed our system...he's been right about everything else, so I don't doubt his numbers).

With a heat pump water heater supplying 100% of the hot water for the year (optimistic, maybe?) and a COP of 2 (my guess...correct me if wrong), the hot water cost would be approx.$249.

So, minimal savings replacing the DSH with a heat pump water heater.

The most savings would be if the heat pump water heater dehumidifies the cellar enough to turn off the dehumidifier down there. We do agree on the savings there (1-2Mwh per year). My number is about 1.2 Mwh. This is for a fairly new (3year old) dehumidifier and a 1000 sq. ft unfinished cellar. This is only if the dehunidifier is no longer needed, though. So that's another $192 savings.

Total yearly savings by my calculation is about $223 by replacing the desuperheater with a heat pump water heater (and it's a pretty generous estimate).

 

[woodgeek]

To be honest...it was a shoot from the hip. sesmith's numbers look good, but I would pick on a couple....

IIRC sloeffle shut down the DSH in the winter (less than 58% DHW), and I doubt that the geo is COP = 4.33 when pump energy is included, prob 3-3.5.

HPWH might get COP=2.5, but with heat stealing in a well insulated basement....let's call it 2.

The dehumidifier is a big factor, and largely unknown both before and after.

Simple payback might be 2 years.

 

[sesmith]

) and I doubt that the geo is COP = 4.33 when pump energy is included, prob 3-3.5.

.

Don't forget, DSH also uses waste heat off the compressor. I'm assuming that's why the estimated COP for my DSH is higher than the estimate for the heating system.

 

[woodgeek]

I haven't forgotten.....the pump energy is a constant, and will have an even larger (proportional) pull down on the COP.

 

[sesmith]

I missed the fact that he shuts his DSH off in the winter. In my climate it would be getting very little use then. In the summer, it would be true that the heat the DSH uses is waste headed out to the loop field. In winter, it is a load on the system, but at even a COP of 3 or 3.5, it's bargain cost hot water. As long as the GSHP sytem isn't undersized, no reason not to use the DHS. Maybe the ideal setup is to use the DSH in the winter and the HPWH in the spring, summer, and fall months,

 

[woodgeek]

In round figures, let's say the COP of a HPWH is 1.75 in the winter, all in (assuming something like 2.3 for the HPWH and the additional being the cost of heat stealing from the geo space heat), and lets assume the geo+DSH is 2.5-3 (lower COP than space heating due to the greater lift to DHW temp).

For normal usage, the HPWH would be $20/mo at that COP, scaling down or the DSH, it would be $12/mo, maybe $8/mo cheaper. What are we talking here...$30-40 per year in theoretical savings for a more complicated setup with seasonal switchover?

Now, here's my ignorance on DSH....will it get to 120°Fin the winter, or would the marathon still need to 'finish' the HW? If the latter, the true COP of the DSH in no better than the HPWH. IF you dig into HPWH specs, you find that the COP is a function of tank temp (lift). When cycling the COP putting BTUs into the cold tank is a respectable 3-4, like your DSH, and then drops to below 2 during the high temp finish, for a cycle average COP of 2.2-2.4 depending on the system.

I'll skip any discussion of loop temps, compressor wear and tear, etc, because both options are pulling very similar BTUs from the ground (in the limit they achieve similar seasonal COPs for the HW). Of course, sloeffle has concerns of winter loop temps, the HPWH operation will cause a small increase in winter loads (not unlike the DSH), because his basement is described as well insulated. If this turned out to be a problem, he could (1) switch it to conventional during very cold weather by switching off the geyser and on the element or (2) buy (hypothetical) envelope improvements, prob related to airsealing his crawlspace or attic.

 

[sloeffle]

That's $352 per year, so you either found a real deal or are maybe off by a decimal point?

Nope, I paid 365$ for a Nyletherm shipped to my door from Tom in Maine. I would send you the eBay listing but it is blocked at work. The COP of the Nyletherm is between 2 and 3 according to one of Tom's You Tube videos. According to the Waterfurnace doco the COP for my particular furnace ( 049 with ground loop ) in my setup is 4.0.

I generally do a see a drop in my electric bill during the summer. During the winter months I do not see any noticeable savings. Due to the lack of energy savings from the DSH I decided that it would probably be best just to shut it off during the winter to help keep my loop temps up. We put in 600' of pipe in the ground per ton so I do have a big enough loop field.