Not solar talk but very General. Need some help.

[C_Heath]

Been lurking (and learning) a lot for a while so I wanted some advice for a friend who is having some major issues with energy consumption in his home and I would greatly appreciate some help in any way. First some demographics. He built the home himself. Built in 2005 or so. All Brick, 2600-3200 sq. ft. Full unfinished basement, 2 car enclosed garage. Its probably a 300k give or take priced home if on the market. The home is insulated very well. He does have many appliances and a family of 5 but all are gone throughout the day to school and work. He has two 12 year old name brand units but uses only one during the winter but for the last 2 years has heated 75% of the time with wood heat when he is in town as he works out of town a lot.

His power utility bill has steadily been $500-$600 per month with one or 2 months being $723. July was $323. As stated earlier, he built most of the home himself so he knows the ins and out of the infrastructure with wiring, HVAC and plumbing. He is just as baffled as everyone else. This has just started in the last 2 years as well. Hence, this is why he added the wood stove. The family has normal routines of showers and clothes washing. There are 2 appliances in the unfinished basement though. An older freezer and a stand up refrigerator. He uses electric to power the heat pump, dryer and water heater but the water heater has a timer.

His POCO is charging .09-.12 per kw/h and have replaced the meter per his request. Today, I took a friend who is an HVAC tech out there. The notioned that he would say that the Strip heat was on but not the fan. After checking, that was not the case. They combed through the panel checking everything they could one by one and everything seemed to be ok as far as amperage. They started the dryer as well and metered it.

So, the tech is stumped as well as everyone else that come out. One thing the tech asked was if the well pump had been checked and the homeowner has checked it as well. Not sure if there is a hole anywhere causing the pump to run all the time but that would be next.

His power company provides a really nice hour by hour consumption meter on his phone. As I looked at it, I noticed that the home would consume 1 to 1.5 kw/h from midnight until around 6:30am and right around 6:30 (shower time I would assume) the particular day I was watching, the kw/h usage went from 1.5 to 15!!!! for an entire hour. That hour was expensive! There were more spikes throughout the day but none that high. It looked to me but I could not see a monthly usage report but by my math, the home was using 215 kw/h PER DAY! does that even sound correct? I may be off on that but it sounds staggering. My home consumes on average of 1700 per month. It seems his is around 6500?

He has all the newer gas windows, burns wood, unplugs most of the phantom items he can and cattle prods the kids during the shower to get them to hurry up. I dont know what else to do but ask some of you guys!

Any ideas?

Thanks in advance!
C

[bcroe]

He needs to find out exactly how those 215 KWH (per day) are consumed. Not just the instantaneous power, but
the cumulative KWH per day (or month). A KILL-A-WATT meter will check 120V devices; there are other means to
check 240V devices. Once the numbers are laid out, it will be obvious where improvements must be concentrated.
Any kind of electric heating is a killer. good luck, Bruce Roe

[Sunking]

Don't worry about the 120 volt devices, they are not the heavy hitters. If I had to guess he has heat pumps and for heat is in Emergency Heat mode. All 240 volt mechanical and electrical is where the big power power goes. So check HVAC, Hot Water, Cooking, etc..

[C_Heath]

Today, I took a friend who is an HVAC tech out there. The notioned that he would say that the Strip heat was on but not the fan. After checking, this was not the case

thanks but I mentioned the Emergency Heat.

[cebury]

If it we're me, I'd buy a TED (the energy detective) and wire it into your service panel. It will tell you per circuit if you select one with thay many CTs. But that'd be overkill once you figure it all out and stop monitoring the usage.
I bought a lower end TED and put one on each of the 120 legs and it totalled my 240 HVAC just fine. Or there are cheaper units like EKM makes watt-meters that I've used on a couple circuits just fine. The ekm 15e can track one leg up to 50amps and is like 50 bucks.

The Kill a watt meter that is frequently recommend here is great for individual indoor appliances between the outlet and plug, its limit is like 1800 watts.

[PNPmacnab]

I have a cheap energy monitor with a donut pickup for current. Lift a wire off each breaker one at a time, pass it through the donut and reconnect. I power off 120V for convenience and just double the wattage readings for 240. It will record total KWH so leave it on for a day or a week. Usage this high will show up as something dramatic. Accuracy is not that important. Without numbers you don't have anything.

[DanKegel]

Wait until one of those hourlong spikes, then go flip breakers off until you figure out which circuit is making the meter spin so fast.

[cebury]

As I looked at it, I noticed that the home would consume 1 to 1.5 kw/h from midnight until around 6:30am and right around 6:30 (shower time I would assume) the particular day I was watching, the kw/h usage went from 1.5 to 15!!!! for an entire hour. That hour was expensive!

15kw inst. demand is very high so almisg surely several things together. The hot water, any local heating (bathroom space heater? Or heat lamps?) And someine could've thrown in a load for the dryer that morning. If you have access to his utility usage it seems like you could just replicate the appliances that were on in the am at 630 if you don't want to drop any money into house panel monitoring. It seems like you are already half way there to finding the culprit(s).

[bcroe]

Get the actual numbers as indicated above, no guessing. Any power monitor should take into account the
power factor, or error will increase. The 240 volt stuff will be the big ones, but smaller loads that are on 24/7
will creep up on you. At the start of my energy campaign I had phantom loads of 300 watts, or 225KWH a
month. Eventually about 80% of that was eliminated. I'll bet you have more. Bruce Roe

[peakbagger]

I have heard of some stiff power usage from hot water recirculation systems that some builders install, they keep the water nice and hot at the taps but effectively are heating the house with electric heat.

[sl dl]

Long shot but I had this happen to me.....turned out to be a cracked wire due to age. Mine was much older. Actually they kept "fixing it" and it kept "breaking". Old wire. Underground. Has he been blowing up appliances. This kind of issue, can't remember what they called it, will cause power surges. My bill tripled 1 month when I wasn't here most of it. Finally had to call consumer protection in my state and they came out and replaced the whole line in. Problem gone.
If you looked at 1 days usage and it looks like something in the house is faulty then it probably is not this issue. but if you see spikes at different times, especially in the rain, as mine was it could be this.

[DanS26]

You gave us a clue when you said that July was half of the other monthly bills.........my first guess is that the emergency heat strip in the heat pump is running almost continuously in the cooler months. Get a second HVAC inspection using a different company.

Next guess is a malfunctioning electric water heater.

[J.P.M.]

I have heard of some stiff power usage from hot water recirculation systems that some builders install, they keep the water nice and hot at the taps but effectively are heating the house with electric heat.

On hot water recirculation systems for homes: I've seen more than a few of those, measured a couple and I'm of the opinion they are one of the biggest energy hog scams around.

A bit of back of the envelope stuff and a SWAG on the loss for an uninsulated 3/4" line per 100 ft. of line length is roughly 2,700 kWh/yr.

Something like this:

Tubing area = 0.1963 ft.^2/ft.
Tubing length = 100 ft.
Tubing surface heat loss = 1 BTU/ft^2 of tubing +/- ~ 10-20 % or so (combined convection and thermal radiation loss)
Average pipe temp. = 120 F.
Average air temp. around pipe = 65 F.

Heat loss ~ [(0.1963 ft^2) * (100 ft.) * (1 BTU/hr.ft^2 deg. F.) * (120 F.- 65 F.) * (24 hrs./day) * (365 days/yr.)]/(3,412 BTU/kWh) ~ = 2772 kWh/yr. per 100 ft. of uninsulated 3/4 " tubing.

Consider also that a water recirculating line will effectively double the heat loss area of a hot water delivery system by approx. doubling the required line length. Most of the hot water will make a round trip from and back to the heat source.

Insulating a line with 1/2" closed cell foam will reduce that line loss by ~ 2/3 to ~ 1,000 kWh/yr. or maybe a bit more based on a less than perfect insulating job. So, At $0.12/kWh that's $120/yr. for a well insulated line that's 100 ft. long. Seems to me that a lot of homes have ~ 200 ft. of hot water line. A recirc. system will approx. double that to 400 ft of circulating line.

Do the math. Looks to me like maybe and up to $40/month or so for a lot of homes for the sole benefit of not waiting ~ 30 sec. for hot water. Pay your money - take your choice.

Common tricks to knock that waste down involve insulating the lines as mentioned, and putting the circulating pump on a timer. Some relief there, but unless the recirc. system is fitted with check valves and the heat source is at or close to the lowest point in the system, it will continue to lose something like about 1/2 - 2/3 or so of the pumping heat due to thermosiophoning effects.

Also, and because it's at least semi uncontrolled heat transfer, there's the necessary consideration of possible/likely increase in A/C load and therefore additional electrical use to remove the heat leaked from a recirc. system to a dwelling during cooling season. That may or may not be somewhat balanced out by heat added by a recirc. system during heating season. Also, a lot of the line loss may be to areas that are not living space and are not heated or cooled. In that case the homeowner is also paying to heat and/or cool places used little or at all. There's also the power necessary to make the pump work.

A lot of folks repeat the logic they've heard from those selling recic. systems, or ignorant tee huggers and planet savers that goes something like this : "Well, you know Mr. Furrbee, it takes forever to get hot water all the way from your tank - that's a waste of precious water !!"

Well, it is and it isn't. First of all, use your head and think before opening the hot water tap. Use more cold water. Been doing it for years and I'm not dead from it. Second,100ft. of 3/4" line contains ~ 1 3/4 gal. of water. Not my money/etc., but that relatively small amount of water is about half what a toilet flush takes - (and on that point and a drift off topic for a sentence or two, I've got 3 low flush toilets - 1 gal./flush - that all use about 4 gal./flush as measured using my water meter and simply measuring the volume of the tanks and seeing how much H2O leaves with each flush. 1 gal./flush my ass.) - Also, water's a lot less expensive as a commodity than energy (a significant portion to most of municipally or water co. service charges have little to nothing to do with the actual amount of water used. FWIW, I pay about $0.01/gal.. My last bill was $95 of which ~ $7.50 was for the commodity). Heating the water in 100 ft. of a cold line takes ~ 0.3 kWh at a cost of ~ $0.12*.3 = $0.04 for energy at $0.12/kWh., and probably similar for nat. gas at usual gas prices, vs. probably something like $0.02 for the water.

I wonder how many homes would have hot water recirc. systems if the owners knew what they cost.

[solarix]

I recommend a good meter like a Fluke 362 with a clampon ammeter to narrow down which branch circuit is the offender....

[bcroe]

A bit of back of the envelope stuff and a SWAG on the loss for an uninsulated 3/4" line per
100 ft. of line length is roughly 2,700 kWh/yr. Something like this:

Tubing area = 0.1963 ft.^2/ft.
Tubing length = 100 ft.
Tubing surface heat loss = 1 BTU/ft^2 of tubing +/- ~ 10-20 % or so (combined convection and thermal radiation loss)
Average pipe temp. = 120 F.
Average air temp. around pipe = 65 F.

Heat loss ~ [(0.1963 ft^2) * (100 ft.) * (1 BTU/hr.ft^2 deg. F.) * (120 F.- 65 F.) * (24 hrs./day) * (365 days/yr.)]/(3,412 BTU/kWh) ~ = 2772 kWh/yr. per 100 ft. of uninsulated 3/4 " tubing.

Consider also that a water recirculating line will effectively double the heat loss area of a hot water delivery system by approx. doubling the required line length. Most of the hot water will make a round trip from and back to the heat source.

Insulating a line with 1/2" closed cell foam will reduce that line loss by ~ 2/3 to ~ 1,000 kWh/yr. or maybe a bit more based on a less than perfect insulating job. So, At $0.12/kWh that's $120/yr. for a well insulated line that's 100 ft. long. Seems to me that a lot of homes have ~ 200 ft. of hot water line. A recirc. system will approx. double that to 400 ft of circulating line.

Do the math. Looks to me like maybe and up to $40/month or so for a lot of homes for the sole benefit of not waiting ~ 30 sec. for hot water.
I wonder how many homes would have hot water recirc. systems if the owners knew what they cost?

I decided to take J.P.M.s input and apply it to my system. I actually measured the length and dia of all
the pipes involved. The 3/4" distribution pipes were fully insulated, so I used 1/3 of their actual area.
The return line is much smaller dia (area) and shorter as well, but not insulated. There were also 8
branches of 1/2" pipe to faucets which don't have circulation, but still radiate. These were estimated
at 4' each of which the warm end was insulated; the faucet end is pretty much cooled most of the
time so I took the effective radiating area at 1/3 the actual length. I have my own well.

0.875" dia Tubing area = 0.23 ft.^2/ft.
0.875" dia Tubing length = 68 ft.
full insulation (use 1/3) effective sq feet = 5.21
0.31" dia Tubing area = 0.08 ft.^2/ft.
0.31" dia Tubing length = 32 ft.
no insulation effective area = 2.56
0.624" tap off dia Tubing area = 0.16 ft.^2/ft.
0.624" tap off dia Tubing length = 32 ft.
no flow, insulated at warm end, effective (use 1/3) sq ft = 1.71
_______________________
total effective sq ft = 9.48
Tubing surface heat loss = 1 BTU/ft^2 of tubing per hour per deg F

Average pipe temp. = 120 F., air temp. around pipe = 65 F

Heat loss ~ [9.48 sq ft * (1 BTU/hr.ft^2 deg. F.) * (120 F.- 65 F.) * (24 hrs./day) * (365.25 days/yr.)]/(3,412 BTU/kWh) ~ =
1340 kWh/yr. (or 50 gallons propane/year).

Here at $.090/KWH or $1/gallon propane that amounts to $120.60 or $50 A YEAR to keep those pipes warm. Since in
these parts the house requires some heat 6 months a year to be comfortable, half that would be discounted as already
being spent. And since the water in the pipes is being heated up by normal operations perhaps 6 hours a day, I'd take
another 75% multiplier. That puts actual circulator running cost here at around $45 for electric or $19 for propane water
heating A YEAR. Feel free to double these if my estimates are off. Obviously YOUR RESULTS WILL VARY. Bruce Roe