
Ask HN: Best way to identify energy waste in a house? - brightball
Our power bill has been a lot higher lately and I&#x27;ve been wondering about ways to track&#x2F;fix it. Any suggestions? Looking for everything from device power usage to things that could cause the HVAC to work too hard.
======
brudgers
Hot weather will cause an AC system to work harder, e.g. San Francisco at 106F
on 9/1/17\. Humidity will cause an AC system to work harder and people produce
a lot of humidity just from respiration and even more from hot showers...and
coming back to hot weather, air contains more latent heat at higher
temperatures given a constant relative humidity because hotter air holds more
water vapor (at constant relative humidity).

It's worth noting that managing humidity is why smaller A/C units (fewer tons)
are often more efficient in practice. Residential A/C units are controlled by
thermostats and an oversized A/C unit (often preferred by consumers because
"I'm no expert, but bigger is better") will short cycle [1].

Or to put it another way, if the air conditioner is running hard the most
likely culprits are the air conditioner and the weather. But since this is HN,
it could be your server racks in which case give them their own A/C...which
reminds me that dividing a building up into many small zones, each with
separate control is a good way to design an efficient system and why I am a
fan of mini-split systems and room air conditioners. The goal of A/C is to
cool people not buildings.

Good luck.

[1]: Short cycling is quickly lowering air temperature to the point the
thermostat shuts off cooling before a substantial fraction of the latent heat
from water vapor has been removed from the conditioned environment by the
system.

------
itamarst
Beyond other advice: a kill-o-watt for 110v plug-in appliances. We found our
TV using $5/month worth of electricity just sitting idle.

Our library actually has kill-o-watts available for lending.

------
arjunvpaul
Where do you live? Not to come raid your fridge, just to see if Its heating or
cooling that you use. There are several passive heating/cooling techniques you
could use.

If, as you say the problem arose "lately", it is probably your HVAC being over
extended. For starters, buy one of these babies
[https://goo.gl/4YFNZt](https://goo.gl/4YFNZt) (you could return it afterwards
:-) and take some images of all the rooms from inside and also from outside
the house. It will basically show you if heat/cool is leaking from your house.

Follow it up with educating yourself using something like this provided by
your local energy company [https://goo.gl/HzY3QZ](https://goo.gl/HzY3QZ) OR
start with a simple checklist like this
[https://goo.gl/wx55iC](https://goo.gl/wx55iC) and make sure all the bases are
covered.

If you want to do spend a little and do a more professional job, get one of
such guys in your area to come do an energy audit of the house
[https://goo.gl/mTmAeg](https://goo.gl/mTmAeg) .

~~~
brightball
Upstate South Carolina. Thanks for the tips!

~~~
arjunvpaul
So its probably really hot there now. One thing you could do if space allows
it, is to plant the right type of trees in a formation like this
[https://goo.gl/nChH4r](https://goo.gl/nChH4r) in the east-west direction.
This way, only the mid-day sun will directly hit your house. This reduces load
on your HVAC system from unnecessarily being used.

For the right type of trees (grows fast, doesn't shed too much and doesn't
fall over in a strong breeze etc), ask advice from a landscaper in
yelp/craigslist. The garden section at some Home Depots might help you out.

More tips can be learned from just googling and learning about Passive Cooling
techniques.

------
mchannon
Other suggestions here are good in terms of how to track it, but I suspect you
don't need to track it beyond what you already know- it's most likely that air
conditioner.

Even if every other electric appliance in your house doubled or halved its
power consumption, it wouldn't move the needle near as much as the biggest
energy user in the house.

If your AC is more than 5 years old, consider replacing it. Not only do they
eventually wear out, wasting more energy, but newer ones can be more energy-
efficient.

Consider buying a cheap mister for your AC's radiator. It uses a small amount
of water to conduct the heat off the coils. Cool-n-save, Mist-n-save,
Mistbox.. may want to soften the water you use to avoid scale deposits.

The smartest thing would probably be to explore a 5kW PV system on your roof.
Not only will it remove heat from your roof but it will also save a lot on
your air conditioning no matter how efficient it is nor how hot it gets
outside. SC's government and utility incentives (visit dsireusa.org) look a
lot like those in PV-friendly states from 5 years ago (which is to say,
ridiculously good for the homeowner).

~~~
brightball
Do those mister's really work? I remember liking what I saw from the promo's
but there seemed to be a lot of people claiming snake-oil.

~~~
brudgers
Evaporative cooling is more useful in dry arid climates. If you live in
Pheonix, AZ, you may get by with nothing but a swamp cooler [1]. If you live
in Phenix City, AL, you'll just get mold because the relative humidity is
high. So if spraying water on your coils will cool them, then a swamp cooler
may be a better option.

At large scale, evaporative cooling works even in humid climates but by large
scale I mean upwards of 20 tons [2] square feet plus a place to put industrial
level noise.

[1]:
[https://en.wikipedia.org/wiki/Evaporative_cooler](https://en.wikipedia.org/wiki/Evaporative_cooler)

[2]: The 20 tons is based on the current Trane US product line. It equates to
upwards of 12,000 square feet of conditioned space.

------
hijinks
Check your air filters in your heater. If they aren't clean then your AC has
to work a lot harder to cool the house since air flow is blocked.

Also another good one is clean the coils on your AC. Its the same concept. If
air can't flow through the coils then your AC will work a lot harder and suck
up more energy.

If you live in a area where it cools down at night and don't have a lot of
humidity, then look into buying a whole house fan. I live in the Denver area
and it will really cool down my house quickly.

------
chipuni
If your power bill has "been a lot higher lately", then it's your air
conditioning.

Take a look at the changes that you've made lately with your power
consumption, and what's gone up. Once you've narrowed it down to your air
conditioning, you can do something about that problem.

(Important note: The biggest use of electricity isn't always air conditioning.
But after a hot summer... it's air conditioning.)

------
mattbgates
If you have children... ha, but seriously, go around your house and unplug
anything not plugged in that isn't charging something. Even if your chargers
aren't connected to your phones, you are still consuming electricity. I
believe its known as "trinklets".

So plugged in, your devices are consuming something like (don't quote me on
this) $.007 per minute or something like that, and then unplugging them, but
leaving their cords plugged into the wall is still consuming something like
$.003. It all can add up over the month.

This includes any ceiling fans... they may be turned off, but if they are
plugged in, it's still consuming resources.

------
shoo
Measure first. Eg for measuring power usage you could borrow a decent quality
power meter. Public libraries near me have them.

If your house isn't well designed and constructed for passive
heating/cooling/insulation that's probably a whole other can of worms to
identify and fix

------
cdiamand
A friend of mine managed to wrangle a device from his local fire department
that measures the heat or lack thereof of whatever it's pointing at. It shows
a picture of what you're looking at, but colors the hot / cold spots. It was
really enlightening to see the different places around the house that heat was
escaping. Food for thought.

~~~
tobylane
Infra-red camera? eg
[http://www.flir.com/uploadedImages/Store/Products/Instrument...](http://www.flir.com/uploadedImages/Store/Products/Instruments/T-Series/t-series-
models-t500b.jpg)

~~~
cdiamand
That's it!

------
chiph
See if your power company offers a home-energy audit. Usually they'll have a
FLIR camera and look for air leaks, uninsulated portions of the house, single-
pane windows, etc. Then look at appliances like the refrigerator, which often
use around 11% of your electricity each month.

------
oblib
Our heat pump had a relay get stuck a few years ago and ran constantly. This
can run up your bill.

