Being an Energy and Environmental Control Consultant I thought I knew all the answers when we built our dream house nine years ago. I would use the same ground breaking direct digital control systems we use in the large buildings, and apply dynamic control concepts to our passive solar house. The passive solar design and the good exterior envelope of the house almost eliminated the requirement for heating and cooling, but close control was still required. The design included room temperature sensors with a "make me happy button". The concept of this push button was that it was pushed to provide heating for a programmed time, with no questions asked. The ability to trend the closely controlled temperatures over several days proved that our requirements for heating and cooling have little to do with the actual room temperature. Our wish for heating often has to do with how we are feeling and what we have been doing, not what the temperature is in the room. When we feel cold no amount of assurance that the temperature is perfect is going to convince us that we are not cold. The logic is; "If we are cold or hot we want heating or cooling, don’t confuse us with that temperature crap". In conventional thermostat systems when we are cold we turn up the thermostat, then leave it there until we come to the conclusion that we are too warm. This control loop has a very poor feedback because the person who was cold may leave the house or start exercising or...??? At least the "make me happy button" gets us the result we want without negotiations. It deals with the logical conclusion that the request for heating or cooling has nothing to do with a requirement for heating or cooling, so shut it off as soon as we perceive we are happy. The temperature trends proved that the request for heating or cooling often does not even change the room temperature, but that satisfaction was achieved.

In addition to using the make me happy buttons for "give me heat now", we also use them to start the heat exchanger ventilation system for the washrooms. This works well and replaces the normal fan switch and runtime timer. But we should have made the buttons stronger. Visiting guests, when told of the concept, seem to relate to amount of heat and ventilation with how hard to push the button. In some cases the button has been pushed right through the backing. One problem may be the lack of feedback as the ventilator is relatively quiet when compared to a typical washroom fan. Often the amount and effectiveness of ventilation is related to noise. So........ we are interfacing with humanoids that want heat when the temperature is OK, and noise to rid the washroom of odors? Maybe that’s why I have trouble understanding interface requirements, and why my computer logic does not work??

With a large house mass and a small heating capacity, night setback was met with varying success. Setback in colder weather caused warm-up to occur about noon. Resetting the setback temperature up as the outside air got colder, and even eliminating setback on the coldest days, solved that problem. Since the coldest days seldom occur energy use is not greatly effected by this routine.

A routine to prevent heating when windows and doors were open was controlled by a cold day decision which was calculated from the weather prediction program. This all went awry when unusual winds warmed up the outside air sensor causing a declaring of not a Cold Day, which held the heating off on a really cold day. This fault was reported by angry humanoids not the computer, as their only defense was pushing the "make me happy button". Once it is cold in a house with a large mass and low heating capacity it takes awhile to recover. But with a little sweat reprogramming, the problem was corrected.

One of the routines that has worked well without intervention is the starting of the heat exchange ventilator based on hot water usage. Usage is sensed by a drop in the domestic hot water temperature which occurs as proven by the trend only when someone showers, dishwasher runs, or it is laundry day. Monitoring the consumption of the hot water heater was a real eye opener as the domestic hot water energy use exceeds the house heating energy. Wash day often used more energy than the rest of the week combined.

In addition, we also control our seven zone sprinkler system from the same panel. This has worked well as we are able to setup the days we wish to sprinkle, plus the timing of each zone and record the run hours of each zone, etc. An ambient light roll up number allows us to miss an irrigation cycle if weather has been overcast for several days. During a holiday a freak lighting storm hit and hung the panel with two irrigation zones stuck on ...........this caused at least some concerns. A recycle of the automation panel would have solved the problem, but this involves special instructions to your house caretakers.

The ability to program a setback schedule for heating, plus the ability to record and trend actual energy consumption for each room has generated the greatest savings. Being empty nesters leaves lots of opportunity to shut down rooms or setback to a minimum temperature when not in use. The "make me happy button" could be programmed to allow rooms to return from setback when pushed several times in succession.

When the project was done nine years ago with a $2000 Canadian computerized panel, the total control cost was very close to similarly functioning conventional control. Low sensor costs and the elimination of setback thermostats, irrigation controller and wiring and installation savings offset the panel cost. The fact is that in the nine years panel costs have dropped to less than $400 Canadian, provide more functionality, and now have Windows and/or HTML interfaces for seamless home network integration. The new low panel cost makes our approach the lowest cost life cycle option for home control. For these concepts to be economically viable they still must be applied to large residential projects, or have concepts canned for large quantities of specialized custom home control designs.