How do I anticipate energy calculations for a changed climate decades from now?
mateohao
| Posted in Energy Efficiency and Durability on
Hello,
I live in a 3C climate zone. I know as time goes on the summers will get hotter, drier, and longer. Rain is already more scarce than the eldest residents can remember; there are anecdotes about rain occasionally ruining Halloween in years past–something that doesn’t happen anymore.
Where I live, I only need an R-20 wall to be code compliant. But will this be suitable for my climate 10 years from now? 20 years? What resources are available to anticipate what my house should be able to handle in the far future?
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I’m rather skeptical that we’ll see significant changes in the near term. In my own area, the past several winters have seen record lows, and this spring has been plenty wet so far (as was last year). I wouldn’t plan for warmer future weather, at least not exclusively.
If you want to play it safe and be ready, the easiest thing to do is to add more insulation. More insulation helps you if it gets hotter, or colder, or even if everything stays the same. More insulation will nearly always reduce energy use regardless of climatic conditions. The other thing to do is do a good job of air sealing everything. After you’ve done those two things, stuff starts to get more difficult and also more expensive. Go after the low hanging fruit first.
Bill
Mateo,
Bill has given you good advice.
We know the general trends, but unfortunately no one can model the changes its will occur in one specific place with any useful accuracy.
Decades from now when your current cooling equipment is likely to have been worn-out and replaced with new and better equipment several times before it could warm more than a few degrees.
I say live for today and do not let anyone convince you that our best days are behind us. I see no reason to believe life will not be better in the future.
Walta
One thing for sure is climate down the road will be more variable. The important part is to make your building more robust. Assume that weather will be more extreme, so design for more wind and more rain. This is more important than insulation, you can always add more insulation but hard to fix wind damage.
P.S. Most places will probably need less insulation and more AC. I've never had to run my AC in May, yet it has been on for a week.
Dynamic pricing for electricity is going to become more popular. Consider design choices that allow one to shift use to when prices are low (or electricity is cleaner).
Air sealing is always good - but not just "looks good", have it tested with a blower door.
That’s a good point. You can set up your home like a poor-man’s version of an ice chiller by pre-cooling with cheap power prior to the on-peak rate starting, then coast longer while on the on-peak rate before needing to run your AC again. Thermal mass in your home acts as a battery in this case. You could conceivably use a hydronically heater slab in reverse as a cold reservoir here if you were to get creative.
I’m on a “time of day” electric rate by choice to save money. I use the Ecobee thermostat which can be easily programmed for complex “this time / that temperature” setups. With such a system, you would run for an hour or two before on-peak (11am for me, weekdays) starts, cooling down to a few degrees colder than you’d normally want. As soon as you get to on-peak time, you change your set point to a few degrees higher than you’d normally want. When you get back to off-peak Time (7pm for me, weekdays), you change again to the setpoint you want. At night we sometimes go a little cooler for sleeping.
You can do the same thing in reverse for heating, but that doesn’t help me much since I heat with natural gas which has no on-peak/off-peak pricing structure so I would only save on blower motor electric use which isn’t much.
Bill
"Dynamic pricing for electricity is going to become more popular. Consider design choices that allow one to shift use to when prices are low."
Really good point.
What other load shifting mechanisms might make sense? A separate circuit for non time critical appliances (eg, heat pump water heater, dishwasher, washer, dryer)?
Can one justify an air->water heat pump plus very large water tank for space heating/cooling? Note that the payback is highly dependent on the max and min prices for electricity. Hopefully in the future the difference will be large. Residential solar without net metering could also play a role.
Ice chillers used to be the big way to take advantage of off peak rates for big commercial buildings: you’d freeze your big tank of water into ice at night when rates were low and then thaw it to cool your building during the day. In my area, on and off peak commercial rates have gotten so close together that ice chillers are no longer viable here on new installations. This is unfortunate since I’ve always like that technology.
For residential setups, the easiest things to do are be creative with your thermostat schedules, and run your washing machine and dishwasher during off-peak hours. Bake stuff off-peak too. This usually isn’t difficult since the off-peak hours tend to be the time you’re most likely to be at home anyway.
Solar works awesome here because it’s output tends to coincide with the on-peak hours. Solar gives you maximum output during the time the energy would be most expensive to buy! This is the next best thing to net metering, and it doesn’t require any special utility contracts. In this setup, you size the solar system for close to your peak daytime load, and it operates as a “peak shave” system cancelling out your utility demand during the on-peak hours. I hope to try this in the not too distant future myself.
If you have an electric car, you can set it to charge at night during off-peak hours. I’ve had my volt configured to charge this way since I got it at the end of 2011. Even the early models had provision for timed start of charging.
Bill
I see this took an interesting turn.
I've been ruminating on these sorts of design elements lately—the ones that may integrate with a changing grid structure.
I wonder what sorts of things may have been shunned or devalued in the past that may again show promise—like thermal mass and related devices, passive elements, less-processed building materials (especially if they sequester carbon), etc.
Storing energy will likely become valuable, as Jon points out. That storage doesn't have to be chemical (batteries). It can be thermal, simple time-shifting (a sort of virtual storage), or other.
Somewhat fringe ideas like phase-change materials for thermal storage (both directions: liquid to solid (ice) for cooling and solid to liquid for heating) which have much higher heat capacities per volume than non phase change 'thermal mass' materials are intriguing. Not sure if implementation of them is currently practical or worthwhile.
It also depends entirely on where you live. Some areas may face water scarcities (many already do of course). Other areas may experience greater flooding. And let's not even talk about mass migrations or socio-economic collapse (not saying it's going to happen, and if/when it does, not for any one reason). In other words, all bets may become off if stuff really sours—worrying about that doesn't seem like any way to live though.
Tyler,
"worrying about that doesn't seem like any way to live though"
About all we can do is keep our consciences as clear as we can by trying to make sure we aren't making things worse - and wait and see what happens.
For sure. Worrying about potential chaos, collapse, and societal decay feels akin to being a school child worrying about 'the bomb'. Worrying about that which is out of our control and standing idly by the biggest 'desk' to cower under won't change our outcome.
Yet contemplating possible future changes and challenges, while embracing some unknown, doesn't seem like a bad idea; for steering purposes. Akin to seeking diplomacy with the Soviets (cold war).
Do we have a choice between being the scared, helpless, children or empowered, informed negotiators? I'm going to at least pretend to be the latter.