Thanks to the climate crisis, we’re guaranteed hotter and wetter weather in the years to come. We’re used to our humid summers in Philly—but hotter and more humid? How are we all going to cope with that? When we cool our indoor spaces with air conditioners, we’re basically pushing the heat and moisture outside, making the outdoors even more uncomfortable. Using AC also means we use more electricity, meaning more greenhouse gases from the power plant.
This was written for the August 2019 issue of GRID Magazine. Read entire column here.
As we gutted a Philadelphia row home, we also planned for it to become a frack-free house. This translates to: No gas appliances delivering fracked gas from Western Pennsylvania into our home. Everything that once used gas would be replaced with electric options.
So far, we’ve happily removed the gas oven / range and the associated gas pipes out of the kitchen. For cooking, we’ve picked out an electric stove. And already own other electric appliances to supplement this: toaster oven, microwave, induction cooktop and crockpot.
But hot water? As with most homes in our city, ours had a tank of hot water, kept piping hot using the fracked gas pipeline coming right into our basement. It didn’t make sense to have gallons of hot water waiting for us, night and day. As I explained to my nephew, it’s like having a tea kettle ready 24 hours a day, for whenever we might want our 2 cups of tea.
So we began looking at on-demand hot water systems, also known as tankless hot water systems. There are gas models available, but of course, we only considered the electric models. All tankless models are certainly more efficient since there’s no energy loss during storage, but the recurring question seemed to be…
Could the on-demand water heater keep up with our demand?
We learned that the average ground water temperature in Pennsylvania ranges between 45 and 50 degrees F. And that we like our showers at 112 degrees F in the winter, cooler in the summer. This means the water needed to be heated 67 degrees (112 – 45).
We also learned that 1 kW of electricity can raise the water temperature by 7 degrees F at a rate of 1 gallon per minute (gpm). This translates to needing 9.5 kW (67 /7) for a 1 gpm flow.
The average faucet flow is 2 gpm. The efficient shower head we’ve installed at every home we’ve been in for the past 30+ years has a flow of 1.5 gpm. We agreed that we both kept it at mid-flow, rarely at the full flow of 1.5 gpm. And so decided that our demand (in the shower stall) could be rounded down to 1 gpm.
The tankless system we decided on is the EcoSmart 11, suitable for 1 shower at a rate of 1.5 gpm for incoming water at 47 degrees F, ideal for our one bathroom apartment! We also agreed that we could coordinate sink and laundry use based on shower use. The shower use would take precedence. If this proved inadequate, our alternate plan was to install a point-of-use model under the kitchen sink. The clothes washer we had selected could heat water on it’s own, if needed.
We’ve used this water heater daily for over 16 months and have no regrets. The installation is in the basement, just beneath the bathroom, about the shortest run for the hot water.
How much electricity used during a shower?
We concurred that most of our showers lasted about 10 minutes, or 0.16 hour (10/60).
Per the specs, the tankless system we decided on was rated for 54A and 220 V, or 11,880 W (54 x 220).
For the 10 minute shower, the electricity used would be 2 kWh (11,880 W x 0.16 hour / 1000), about 26 cents at our current utility rate.
The newer packaging now has a yellow EnergyGuide sticker, showing that it uses about 622 kWh annually. I’m reminded of the electric water heater at another house we lived in. It had a 40 gallon tank and used about 4700 kWh annually, over 7 times as much! Talk about an efficient way to get into hot water, with more space in the basement…
We wanted a frack-free, all electric, emissions-free home. So when we needed to move, we decided on a small house, a classic Philadelphia row-home offering about 1300 square feet of living space.
Getting into hot water
When we removed the gas hot water system, we replaced it with an on-demand electric system, with no storage tank. The main benefit is that water is only heated when needed. Another benefit is that this freed up space in the basement.
[include research about calculating size]
We replaced all the appliances with efficient electric ones – the fridge, the stove, the washer, the dryer, ceiling fans & double-pane windows. The fridge has a mere 10 cubic feet capacity, enough for the basics for our 2 person household, but not enough to stockpile! Though people with induction cooktops swear they don’t miss their gas stoves, we opted for a basic glass topped free-standing electric oven / range. The washer is a front loading machine; the electric dryer has heat pump technology and needs no venting to the outside; it drains water into the laundry sink, much like the washer does. The ceiling fans do a marvelous job circulating air the 9 months of the year when our windows are open; so much so that we haven’t missed air conditioning.
Oh, another feature of this smallish house is that it has a 2-car garage. Since the 2 of us share the one all-electric car, we have space for a variety of bikes in the second garage, adding to our multi-modal zero-carbon transportation options. How often does one get to show off a garage wall, complete with EV charger and solar inverter?
We also removed the gas boiler, which once pumped hot water thru the house via radiators. This too freed up space in the basement.
We insulated the basement ceiling, for a warmer first floor. Since our rowhome has neighbors on both sides, we focused on reducing the drafts along the exterior walls. With new windows, and newly framed exterior walls, we added insulation to the exterior walls.
We’ve made the first floor living space so air tight that we often end up opening a window after a shower. There are plans to replace the non-functioning ventilation fan. And so far, have found that the inside temperature only drops by a couple of degrees overnight, even with the space heater off during the night. It seems humans create heat too, which can maintain the heat in a tight space. I’ve heard it to be equivalent of 100 Watts per person. For now, we plan to ride out the winter using space heaters. Next year, we’ll consider investing in a ductless mini-split system.
Powering it all with rooftop solar
Even before we made an offer on the house, we checked for interconnection issues on our electric utility, PECO’s map for interconnecting distributed energy resources (DER). This was in April 2017. The sellers disclosure gave no date for the roof, and the home inspection report stated that the roof was in fine condition, so we signed for it in June 2017. When we finally got a solar installer to assess how much solar this roof could hold, now November 2017, we were advised that we needed a new roof. Having never needed to replace a roof in all the houses we’ve lived in, we spent the winter finding a roofing company who would do the job. Finally, in May 2018, the roof was recovered with another layer. Another quote and another site visit by another solar developer and by July, we’d signed the contract. What were we getting?
In terms of equipment, we were getting22 panels, each rated for 305 Watts, plus 22 optimizers, one inverter, one AC disconnect switch and one PV production meter. The optimizers, one for each panel, ensures that if one panel fails, or has cloud cover, the others keep on generating.
cinder blocks to weigh down panels
laying out the mounting tracks
flar roof with panels
capped chimney – zero emissions!
The system would be 6,710 Watts (22 x 305), generating 7,811 kWh annually, averaging about 650 kWh monthly.
The fully installed system cost was $19,459, which works out to $2.90 per Watt (19459 / 6710).
We get a 30% Federal tax credit, meaning 30% of the system cost can be deducted in April 2019 when we submit our 2018 tax returns, a value of about $5,838. This means our out-of-pocket cost would be $13,621.
I remember when I bought another house, about 13 years ago. We got proposals from 2 different solar developers, both around $18,000 for a 2,000 Watt system, which translates to $9 per Watt. Compare this to the $2.90 per Watt we obtained today! Prices have indeed dropped.
People have asked, but prices will keep dropping, right? So we can wait a few more years to get a better price? Afraid not. Though prices for the equipment have gone down, a large portion of the cost is the installation, which is all local labor. We need to remain fair to the work force climbing ladders and walking on roofs in all weather.
Looking at a recent electric bill, our current electricity rate is $0.13517 per kWh, the sum of distribution, generation & transmission charges ($0.06710 + $0.06275 + $0.00532).
Our rooftop is expected to generate about 7,811 kWh annually. At our current electricity rate, this electricity would be valued at $1,056 annually (7811 x 0.13517). This is $1,056 that we won’t have to pay each year.
Assuming this system will remain on the roof for about 25 years, ignoring degradation of production and increasing electrical rates which could easily balance each other out, the electricity this system could generate would be 195,275 kWh (7811 x 25) and valued at at least $26,375 (1056 x 25).
Over the 25 year life of this system, it would generate 195,275 kWh, which is equivalent to an electric rate of $0.0698 per kWh (13621 / 195275). About half the rate that we’re currently paying. Turns out we’re both lowering, and locking in our electricity rate for a while.
Since we paid $13,621 for the system, and annual generation is worth $1,056, the system would pay back for itself in 12.9 years (13621 / 1056), after which, we’d have 12 years of free electricity. Return on investment would be 7.75% (1 / 12.9). So much better than money in the bank!
So, invest in the local energy generation potential of your rooftop. Having lived in this all-electric house for the past 9 months, our electricity usage has been 6,000 kWh. I can say the experiment of living in a frack-free, emissions-free row-home is going well.
Of course we’ve all heard of and used LED lighting — as string lights over the holidays, and perhaps a somewhat expensive replacement bulb for an existing fixture. During our current rehab, we needed to replace ceiling fixtures and selected ones that highlighted the uniqueness of LED lighting. This meant the fixture wouldn’t have any screw-on replacement bulbs.
For the eat-in kitchen, we selected a track lighting fixture with 6 lamps. Together, 6 lamps together would consume about 40 Watts. The flexible track allowed for more variety in positioning the lamps and by the time we’d installed 3 of the lamps, we felt the room to be bright enough! We settled on 5 lamps.
The average rated life of these lamps? About 50,000 hours. This means we could use them for about 4 hours a day for over 40 years. It’s hard to grasp that there are no bulbs to replace — not quarterly like with incandescent bulbs, not every 5 years like with compact fluorescent bulbs, but 40 years!
Sadly, these lamps are planned for obsolescence after that, but I’m sure the next person living in this space may have their own ideas for lighting up the dining area. And the mostly-metal components mean this fixture could be recycled at end of life.
For a hallway, we selected this ceiling fixture. Again, to showcase LEDs and the no-need-to-change-bulbs feature.
That many of us have partners, neighbors, a car-sharing system with a car parked in walking distance, bus and trains also with stops in walking distance, and yes, a walkable neighborhood – privileges enough to only occasionally warrant needing your own car.
A privileged perspective? Yes. But also paradigm shifting.
Last summer, I wrote about staying cool with fans. This summer, I’m sharing lessons from Hap Haven, our region’s long-time energy efficiency specialist. This essay was originally published in the June 2016 Shuttle, a monthly publication of Weavers Way Co-op.
The “dog days” of summer will be here soon; high temperatures and high humidity. This phrase was created by the Greeks and related to the time of year when the Sirius constellation rose with the sun. It’s a time when seas “boil” and people go mad. While I’m not certain about the seas boiling, we all understand the physical and emotional problems we experience with hot, humid weather. Skip forward to 1902 and we find Willis Carrier inventing modern air conditioning. Since then two things have happened. First, electric companies have collected hundreds of millions of dollars from their air conditioning customers. Second, many people have forgotten how to stay cool without air conditioning. Fortunately for us, there are still many non-AC strategies available. Here are just a few:
SHADE: Staying cool is easier in the shade. This is true for your home, as well as for you. It helps if you have large trees that cast long shadows, but not everyone has older trees around their homes. To those people I say, “Plant one for the next generation”. In the meantime buy an umbrella, install an awning or build a trellis. Nothing has to be fancy. A king sized sheet tied between poles will work just fine to block the sun’s radiation. You might be surprised that the temperature difference between sun and shade can be 30 degrees. One cautionary note about plants; they block sunlight, but they can also raise the humidity level near them. Higher humidity means lower comfort so give yourself plenty of room between your patio and plants like vines on trellises.
REFLECTION: If you cannot shade a home, the next step is to reflect the sun as best as possible. If you need to purchase new windows, choose ones that can reflect part of the sun’s heat. Go to the manufacturer’s web site to see how much reflection you should have. You need more reflectivity in hotter climates. Some new windows even allow you to “dial-in” the shade and reflectivity you need. These windows have reflective mini-blinds inside the window. Assuming that your windows don’t need to be replaced, window film is a good second choice. Thousands of homes and commercial buildings in the Delaware Valley have been retro-fitted with reflective film to cut down on summer heat gain. Typically, you put the film on west facing windows or windows that get direct sun for more than a few hours every day.
Philadelphia has more row homes than any other city in the USA and most still have black colored roofs. The black color turns the top floor into an oven during the summer, but this can be changed. A new trend in flat roof rehab is the white roof. The elastomeric white roof coat has a lot of limitations in terms of when and how it is applied, but once applied, it is far superior to silver or black (oil based) roof coatings.
MOVING AIR: Fans come in every shape and size and continue to be an important way to stay cool. Most fans, such as a desk fan or even a ceiling fan over the dining room table or in the bedroom, are designed for local cooling. Fans cool you by evaporating your sweat. Changing liquid water into vapor (evaporation) removes energy and, in turn, cools your skin. Remember to drink water to replenish the water evaporated from your skin.
There is another type of fan that is very effective, but not for cooling people directly. It’s called a whole house fan. Some older homes have them, but they are rarely used properly. The whole house fan’s job is to cool the house. Yes, the moving air will help to cool you as well, but the fan is designed to remove the heat built-up in your house during the day. Whole house fans and window fans should not be used unless the outside temperature is cooler than the inside temperature, otherwise you are just going to heat up the inside.
SEAL THE SHELL: You wouldn’t walk outside with holes in your rain coat, but your home has thousands of little, and not so little, holes. These holes allow your nice conditioned air to escape and hot humid air to come indoors. Sealing your home used to mean caulking your windows and weather-stripping your doors. That’s a good start, but just a start. Modern air sealing contractors use computers and powerful fans to find out how leaky your home is, where those leaks are and which ones are cost effective to seal. Sealing the shell means you get to control how and when your home interacts with the outside weather.
LIFE STYLE: Philadelphians have historically closed up shop and vacationed in the Poconos, “down” the shore or to any body of water that could provide a cool dip. One all-time Philadelphia favorite is the fire hydrant sprinkler. Staying cool before air conditioning demanded a slower life style in the summer, maybe something we should consider again.
So to wrap-up, the easiest way to keep your home cool is to open up your windows at night then close them during the hot day. Keeping cool is a dance between you and the sun. Use whole house or window fans at night after the outside temperature is lower than the inside temperature. Use personal or ceiling fans during the day. Shade the house where ever possible. If you do all these things, you will only need your AC when there is a heat wave or to knock down humidity levels. Either way, if you do all these recommendations, you shouldn’t need to run your AC more than about an hour a day.
And to lighten the message, here’s a humorous reflection on seasonal clothing for the office: Frigid Offices, Freezing Women, Oblivious Men. Please re-assure me that Mt Airy men are different, that we heart summertime under the fans and under the trees.
If you found any of Hap’s material useful, or are considering a home energy audit, I know Hap would love to hear from you. He is reachable at firstname.lastname@example.org.