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Ridiculous. Depending on where you live you can save more money by simply using a good size fan blowing cold air into the house at night during the summer. We

Ridiculous. Depending on where you live you can save more money by simply using a good size fan blowing cold air into the house at night during the summer. We did just that this summer and did not have to use the air conditioner at all, even during days where daytime temperatures reached well over 100 degrees. On some nights we could get the house down to 65 degrees overnight. The $250 fan paid for itself in less than a month! Total cost of running it 6 to 8 hours per day was less than $10 for the month. This was an experiment to determine whether or not a whole house fan would be a worthwhile investment for next year. Obviously, it is. Next on the list is converting the A/C and heating system to what's known as a "zone" system. Why heat or cool several thousand square feet of a home when you only need one or a few rooms to stay warm or cold? Next would be what I would call "intelligent flow" management. This is of particular value if you live in a two story home. How is a single thermostat on a wall in the family room downstairs going to make decisions about what is best for heating or cooling the upstairs bedroom? Well, it can't. What you can do is have sensors in every single room as well as a way to pump air to and from various locations. Cold air will accumulate downstairs. Hot air upstairs. When the downstairs is comfortable in the winter the upstairs is boiling hot. By using this "intelligent flow" concept the system would simply look for suitable sources of what it needs, say, hot air, and choose to use the least costly source before moving on to a more expensive solution. If the upstairs has three really hot rooms and only one room is occupied, you can pump that hot air back downstairs rather than engaging the furnace. If the sun is keeping the solar collectors nice and hot, use that instead of burning fuel. Following that is some combination of geothermal and solar assist. A simple $20 microprocessor board with some relays and a few sensors can easily manage a set of valves to select a heat source or sink that is more energy efficient than using a compressor or a furnace. Granted, some of the above would cost far more than a $250 gadget to implement. However, it should be obvious that they would more than pay for themselves in relatively short order, particularly the first couple of options. The greater point, I think, is that home energy efficiency is a much larger problem that cannot be addressed in an meaningful manner with a wifi-enabled gadget on a wall, no matter how cool it might look. The good news is that, if we take a serious look at how we build our homes and change the approach the savings can be absolutely monumental.

nitrogen 15y ago
All of these things can be automated. Since the Nest is connected via Wifi and Zigbee, a future firmware upgrade (or an external controller) could add support for a Zigbee-connected fan controller. If the outside temperature is in the direction of the target temperature, turn on the fan. It sounds like you're in a desert-like area with wide temperature swings. The learning system when integrated with your zone system could figure out how cold you're willing to get at night to store cold air for the day, or even use unoccupied rooms to store very cold air to be released into the house throughout the day. I agree that a thermostat alone isn't enough to save significant amounts of energy, but this does have the potential to get get some smart technology into more homes, where it can be expanded later to include everything you describe.
- algoshift 15y ago
  The "Nest" is simply the wrong approach. By itself it is nearly worthless (my not-so-humble opinion) for anyone but the most technologically incompetent thermostat users out there. And even then, you'd have to wonder. Where is the data on how many people can't or don't program their thermostats? Now, some people might buy it just because it looks cool on the wall, and that's OK. A real thermal management system for the home does not start with a high-design thermostat on the wall. You need multiple types of sensors in every room and multiple outdoor points. You need to change the way airflow can be channeled around a home. You might even need to change the paradigm and heat/cool objects that can provide thermal inertia (like the floor or walls) rather than just air. You need to be able to selectively inject other heat sources or sinks into the system. You need solar thermal panels and geothermal heat exchange system in the ground. As far as control, a very simple embedded PC board running embedded Linux would be the "lazy" way to build it. It would actually be overkill, but there's an argument to be made for the COGS aspect of it. Any number of relatively low cost embedded boards running very simple embedded software could monitor the sensor array, make decisions and activate valves, fans, etc. as needed. I guess what I am saying is that you really can't fix the problem without engaging in a fundamental pivot from what we've been doing to thermally manage homes for the last, say, 100 years. Having said that, it is a lot easier to sell a cool looking $250 gadget than asking someone to spend $5,000 to modify their home. Even though the gadget is very likely to not do much and the more extensive home modification is almost guaranteed to save the home owner thousands of dollars per year. Talk about an opportunity for government stimulus!

nitrogen 15y ago

All of these things can be automated. Since the Nest is connected via Wifi and Zigbee, a future firmware upgrade (or an external controller) could add support for a Zigbee-connected fan controller. If the outside temperature is in the direction of the target temperature, turn on the fan. It sounds like you're in a desert-like area with wide temperature swings. The learning system when integrated with your zone system could figure out how cold you're willing to get at night to store cold air for the day, or even use unoccupied rooms to store very cold air to be released into the house throughout the day. I agree that a thermostat alone isn't enough to save significant amounts of energy, but this does have the potential to get get some smart technology into more homes, where it can be expanded later to include everything you describe.

algoshift 15y ago
The "Nest" is simply the wrong approach. By itself it is nearly worthless (my not-so-humble opinion) for anyone but the most technologically incompetent thermostat users out there. And even then, you'd have to wonder. Where is the data on how many people can't or don't program their thermostats? Now, some people might buy it just because it looks cool on the wall, and that's OK. A real thermal management system for the home does not start with a high-design thermostat on the wall. You need multiple types of sensors in every room and multiple outdoor points. You need to change the way airflow can be channeled around a home. You might even need to change the paradigm and heat/cool objects that can provide thermal inertia (like the floor or walls) rather than just air. You need to be able to selectively inject other heat sources or sinks into the system. You need solar thermal panels and geothermal heat exchange system in the ground. As far as control, a very simple embedded PC board running embedded Linux would be the "lazy" way to build it. It would actually be overkill, but there's an argument to be made for the COGS aspect of it. Any number of relatively low cost embedded boards running very simple embedded software could monitor the sensor array, make decisions and activate valves, fans, etc. as needed. I guess what I am saying is that you really can't fix the problem without engaging in a fundamental pivot from what we've been doing to thermally manage homes for the last, say, 100 years. Having said that, it is a lot easier to sell a cool looking $250 gadget than asking someone to spend $5,000 to modify their home. Even though the gadget is very likely to not do much and the more extensive home modification is almost guaranteed to save the home owner thousands of dollars per year. Talk about an opportunity for government stimulus!