Part 1: Introduction to Winter Energy Audits
Here in the mid-Atlantic and Northeastern U.S., we’re getting hit by another deep freeze. Those in the center of the country are probably thinking we’re wimps for complaining about single digit temperatures, but hey, it’s all relative. For us, it’s darned cold!
I’ve been getting a number of questions recently, spurred on by the low temps and associated HIGH heating bills. People are asking: “Help! I got my latest heating bill and it’s astronomical. What can I do to reduce it?” or, the other side of that coin is: “Brrr! My family is freezing. I’ve got the heat cranked up but it’s still cold and drafty in some rooms. What can I do make it more comfortable?”
We’re going to walk through a virtual energy audit “live” so you can follow the thought processes and troubleshooting with me. Hopefully, this will allow many of you to go on to diagnose your own issues and end up with a home that is more comfortable, efficient and safe.
Along the way, drop your questions into the comments below the posts, and I’ll do my best to incorporate answers into the article or answer them in the comments.
Let’s get started!
Edit: rather than doing this as one humongous post, I’m going to break each section into a different post. This should make it easier for people to find the pertinent information and step through the process without it getting too overwhelming.
We keep getting hammered by the PECO bill, despite doing some things we thought would improve efficiency like new siding, new windows in part of the house and a new roof in the past 2 years. Not to mention a new hot water heater last month. We rank #98 out of 100 similar homes in efficiency, according to PECO. Not good. Apart from replacing more windows, where should we start?
Sometimes those comparisons can be misleading since homes use a variety of energy sources for heat, and PECO only tracks gas and electric. 98th out of 100 is a pretty big red flag, so it does sound like there’s something going on.
When I approach these problems, I like to start by determining just how bad the problem is. PECO has tried to do this giving you that 98/100 number but I don’t trust magic numbers other people come up with, so we’ll do this starting with a blank slate.
An example: High heating costs
My heating costs are much higher than a friend’s down the street. They have basically the same size and style of home. There’s got to be a big problem, right?
Not necessarily! I once had this exact call. Heating bills more than twice as high and the house was a new townhome which should have been very efficient. It turned out, the heating system ran on propane and they were forced to by propane from the association for over $5.00/gallon!!! This was years ago and I bought propane for my home for less than $2.00/gallon. Same home. Same fuel. But how you buy the fuel can change the heating bill by crazy amounts.
This is the type of thing we want to take into account when doing these comparisons. But it can get “mathy”. How do you compare oil vs. gas vs. propane vs. electric heat pump vs ???
There are some not-so-secret formulas that energy auditors use to compare homes. In a nutshell, what you want to do is figure out how much energy is being used by the home, independent of the fuel. How? Using some really simple math.
|Fuel||Units||BTUs in a unit|
|Propane gas||Cubic foot||2,550|
Reference: The Engineering Toolbox
What’s a BTU? The Engineering Toolbox – Units of heat
So the first thing we can do to help with our comparison is to convert the home’s energy usage into the universally comparable BTU unit.
This works great if you heat with oil, gas or propane but electricity is more problematic since it’s not immediately obvious how you separate the electricity used for heating from that used to run your lights and appliances. In fact, oil, gas and propane can get confused too because you might heat your water with the same fuel you use to heat your home. We’ll get to this, but let’s dive into that later. Right now, we’re just introducing some of the basics.
For now, assume that we’ve got some magic that allows us to meaningfully come up with a number for heating consumption. Now what?
Let’s do a preliminary assessment
Home and family background:
- home style (i.e. colonial, rancher..)
- square footage of heated space (include the basement unless it’s insulated and sealed under the first floor)
- number of people (i.e. two adults, one infant, one teenager who takes long showers)
- Heating fuel (i.e natural gas, propane, oil, or with electric heat, like a heat pump or baseboard electric heaters)
- System type: furnace (which uses heated air), boiler (uses water/steam circulated through radiators or baseboard heaters or radiant tubing in the floor), or electric baseboard heaters.
- Efficiency, if you know it. I can look it up if you give me the brand and model
- Typical thermostat setting (i.e. set to 75F all day and night)
- Finally, if you don’t mind, share your utility consumption (not cost) for the last year. For the analysis, it’s best to review all the bills for a full year (or more)
- If you have your own tanks, like for propane or oil, you typically won’t have month to month billing or even year intervals so that gets more complicated. In that case, the more bills we can review, the more accurate the analysis will be.
Any other potentially useful information:
- For example, if you have a new baby, chances are good that you’ll be using more hot water and keeping the house warmer than in the past
- If you have other high consumption items, like a hot tub, pool, steam shower, pond, waterfall, etc.
- There’s an infinite variety of things that can affect energy use. I’ve done these analysis for people who had additional apartments using their energy that they didn’t mention in the assessment. Or a tropical greenhouse that’s kept at 85 degrees during the winter.
That should give us the basic info to get going.
Until next time….