Saving Energy in Your Home – It’s All About the Heat

by Engineer Designer on August 9, 2010

Energy is heat. Saving  energy is mostly about heat management. Let’s cover 10  basic actions to reduce energy usage in your home. These apply to new construction and existing residences. First, some basic science: A. Heat energy flows from hot to cold. Its speed of flow increases as the difference between temperatures increases B. Heat flow is reduced by insulation. C. Heat can be pumped in the opposite direction – from cold to hot. Air conditioners and heat pumps do this. Pumping heat is cheaper than created heat – about 1/3 the cost or less.. D. Any heat that enters your home during the summer must be removed by your air conditioner. E. The green-house effect is like a one-way check valve which allows heat to enter but not leave. Heat from sunlight must be stopped before it passes through the glass – not after. F. Passive operation just happens by its nature. It requires no energy. Okay – so based upon these simple rules, here are 10 basic actions that will improve a home’s energy efficiency which will save you money. I’ll mention the rule and then what you can do: 1. Rule B - Insulate your home to the max. Few actions will give you a better cost to benefit ratio. This is also passive (rule F). 2. Rules D and E - Large overhangs – this reduces sunlight into the home which would have to be removed. This is passive (rule F). 3. Rules D and E - Reduce or block windows on the western side. If you are designing a new home this can be easy. This is passive (rule F) 4. Rule E - Use reflective glass. Shades and curtains will not work. They will heat up yet not pass the heat back out the window. Your air conditioner will have to remove that heat. You must stop the heat before it goes through the glass. This is a passive method and will save you lots of energy and money in the summer time. 5. Rule A - Place foil on the bottom of the plywood roof sheathing of your home. This is easiest to do while building a new home. If your home exists, then consider a radiation barrier in the attic. This will keep the attic cooler. This is also passive (rule F) 6. Rule A – Ventilate the attic. This can be passive or active. It reduces the attic temperature which slows the flow of heat into your home. The active, but effective, way is with a powered fan system which operates only at high attic temperatures. An advantage is that this will not operate in the winter when you DO want heat flow into your home. The passive method of ventilation is by effective venting that operates when the wind blows. This is excellent in the hotter states. This requires good air flow both into the attic and out of the attic. 7. Rules A and B - Place the air conditioning ductwork inside the cooled space of the home – not the hot attic. This reduces the heat that flows into the ductwork which eases the work load of the air conditioning system. This is easiest done in new construction. it can be also be done by wrapping insulation on top of the ductwork and not placing any between the duct and the interior of the home thus thermally connecting the duct to the inside temperature. This is also passive (rule F). 8. Rule D - Water heaters should be outside of any air conditioned space. They leak heat. If they leak heat into the home then the air conditioner has to remove it. This action is passive. 9. Rule D - Dryers, ideally, should be outside air conditioned space for the same reason as water heaters. This action is passive (rule F) 10. Rule C - Most water heaters heat their water by running electricity through coils. As an alternative heat can be pumped into the water less expensively. One way to do this is to route the heat being pumped out of your home straight into the water heater. This has multiple advantages. It even works in the winter because the heat being pumped from the cold air outside (this is how a heat pump works) can be used, in part, to heat the water. Per Rule C, pumped heat is cheaper than created heat. Considering the basic rules you can think of your own ideas of ways to save energy and money. Remember, it is all about the heat.