I often write about saving energy, improving efficiency, and lowering your planetary impact... so it’s time for me to come clean and show you my efforts to reduce my carbon footprint. When I first designed my home back in 2000, I wasn’t thinking energy costs were going to skyrocket. Instead I went for good efficiency, but not great efficiency... I’m paying for that now. Even though our home is built from solid concrete poured walls with very high "R" factors, the overall open design allows large amounts of leakage through many avenues such as doors and windows. Along with the basic window films, improved insulation, and better living habits we still struggle trying to keep our home comfortable, yet efficient in the use of electricity and propane gas...
I’ve given this much thought over the years and have recently embarked (as mentioned in my prior post, "Ignorance is Bliss") on a massive project to automate, well... just about everything that can be automated in our home. The idea is to instrument everything (or most things that use power) to understand where the energy is going and to use that information for making decisions on energy use. For example, if the TV and lights are on in the family room and the alarm system is set to "AWAY" mode, then the system should turn off the TV, adjust the thermostat to save power and turn off all the lights. In everyday life, we are so caught up in our schedule that remembering to do these simple things falls far down on our list. A "Smart Home" that knows your lifestyle can save you power if it is properly equipped - that’s where "getting your hands dirty" comes in... however, it feels like I’m trying to move an eight lane highway without disrupting the flow of traffic - not so easy (see my wiring closet photo below).
I never thought about how isolated our home's systems were until I began this project. The lights were originally manual switches (I was the automation) which I replaced over a period of a year with Universal Power-line Bus(UPB) smart switches that are networked together over the power line (no new wires). The thermostats were individual manual units without setback or other communications ability. The hot water heater is gas (propane) and is simply on or off... same with the recirculation pump. The appliances have no power metering or timing ability and cannot communicate with anything - except a human operator. The list goes on... so you can see the complexity of trying to tie all of these disjointed systems together as well as adding the sub-metering ability.
So I’ve begun by prioritizing the largest users of power that I can control... My list is HVAC, Lighting and hot water (propane). I need to know what’s on as well as the state of the home (security set away or home, time of day, weather conditions, etc.) to make proper decisions. The lighting system is 90% complete - most all switches are automated and networked so I can address a single unit or using the protocol, address all units at once via "links". These links are pre-programmed to take a switch to a certain level (on, off, 20%, etc.). So using an "all off" link, I can turn all the lights in the house off in one command.
The HVAC is a bit more complicated due to multiple air handlers... they need to be coordinated so they are not fighting each other to cool or heat the home. A zoned system would have been much better (I wasn’t watching the store that day...), but we have what we have. So, replacing each thermostat with a computerized setback version was the first step (and most reasonably priced solution). This has worked to greatly reduce our consumption in general, but there’s still money on the table. The next step is automated thermostats with communications ability. These can be networked (RS-485, UPB, etc.) so that computer software can force a condition (off, setback, etc.).
The hot water is simpler since we have a recirculating pump that can be turned off - this limits how much water is being heated and can dynamically be turned on when people are home thus saving propane. The appliances are a different matter. There have been talks for years of appliance communication standards so that HA systems can have control (the universal remote for everything, etc.). Each appliance manufacturer had their proprietary scheme of how it should be done, and after years of trying to come to a common standard, it fell apart. This was partially due to a lack of a "need" - no one could rationalize why someone might want to control their washer, dryer, oven or dish-washer from a home computer... until oil prices shot up sending electricity costs through the roof. I personally felt that one and I’m sure you did too. However, no one in our home has finished cooking and left the oven on (so far), so that’s pretty low on my priority list...
If you want to know more about the ancient attempts for unifying everything in the home, check out the EIA-600 CEBus standard... some really great OOP concepts, but it never flew. Also UPB, INSTEON, and Z-Wave are all lighting (and other equipment) control standards with products available today... I’ll keep you updated as I try to finish what I’ve started, but as they say, "The Blacksmith’s kitchen often has wooden utensils". Till next time...
