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Net Zero Energy Home – 2020

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Net Zero Energy Home – 2020

Net Zero Energy Home

Net Zero Energy – 2020

Net Zero Energy HomeIf you live in California, you may hear this phrase, Net Zero Energy.  If you are looking to build a new home, it’s not in effect right now, but it is coming.  Net Zero Energy (NZE) is a new energy standard that California has adopted and goes into effect in 2020.  What it means is that all new homes built after 2020 will need to produce as much energy as it consumes. In a future post I will talk about how you can achieve the NZE goal for your new home.  It may sound like an impossible task, but building techniques and technology are helping to make it a reality. While it will not be fully implemented until 2020, parts of those requirements are being phased into the energy code.  Today I will talk about how NZE affects your current home or remodel

Title 24

The California Energy Code is called Title 24 after the section of the building code that states the energy requirements for new and remodeled homes.  While the focus has been on the NZE standards for 2020, California has been updating its current code bringing it closer to the standards that will be required in 2020.  The latest changes to the code occurred in 2016. They focus on four primary areas of your home: Building Envelope, Attic Space, Lighting, & Water Heaters. Let’s take a quick look at each one.

Building Envelope

Title 24 is always pushing for better-insulated homes because that is the cheapest way to add energy savings.  The building envelope (the exterior walls of your home) is made up of exterior building walls, doors, and windows.  The better insulated the walls, the more energy you save; whether it is heating or cooling. Exterior walls should be framed with 2×6 wood studs instead of 2×4 wood studs. Changing to a 2×6 wall is a 50% increase in the thickness of the wall insulation that we can use.  That allows for fiberglass wall insulation rated at R19 instead of R13.

Many Parts Of The Building Envelope

The building envelope is not just wood studs and insulation but includes doors and windows.  Here you are trying to design an energy efficient home while punching holes in it with doors and windows.  But there are ways we can increase the energy efficiency of the doors and windows we use. Using insulation doors is one way to improve the building envelope.  Dual paned windows today are what I use today. I can’t remember the last time I specified a single pane window if I ever did. I will specify windows that are dual paned with some type of gas between the panes to increase their insulating quality.

Mind the Gaps

It is not just what you put in the openings but how you seal them.  We are designing homes that are tighter. That mean sealing the gaps around doors and windows.  These gaps are usually covered up with trim (wood trim), and they would leak like a sieve. Now we are filling these gaps with spray foam insulation.  There are usually foam gaskets around electrical outlets and light switches to eliminate more gaps.

Attics

The attic space has been a place where heat leaks from your home.  Insulation at the ceiling of a house was the standard, and the ductwork in the attic space was exposed to unconditioned space.  That is no longer allowed by Title 24. If you have insulation in the ceiling, cold or hot air is right above that layer, and your heating system is still exposed to that air.  Yes, the ductwork is insulation, but R6 insulation is not enough. Additional insulation will be added to the roof deck which keeps the attic temperature closer to ambient, improving the home’s heating and cooling performance.  That also means the ducts for your heating and cooling system don’t experience wide swings in temperature. Minimum R-values for the attic space is R-22, but I typical call for R-30 for added savings.

 

Lighting

The Lighting changes are just a natural evolution for Title 24.  We have migrated to fluorescent from incandescents lamps in previous codes; now Title 24 is requiring that all luminaires ( a fancy word for bulbs) be LED.  That is relatively easy since there are so many choices of LED lighting fixtures. The code refers to them as high efficacy fixtures. Rooms are equipped with occupancy sensors or dimmers.  These new switches will turn off the lights in a room when no one is in the room. I have been adding LED light in all my plans for the last two years. They are convenient and offer a lot of flexibility.

Water Heaters

Title 24 essentially kills the traditional water heater tank, well maybe not as drastic as that but we are moving closer to that day.  The idea of having 40 gallons of water in your garage being heated is dead. Tankless water heaters are becoming the standard all new home and water heaters that are replaced in remodels.  That is because when they are used in a design, the energy efficiency can be traded out for other areas of your home (like more glass area). Fortunately, technology has caught up with the requirement.  There are many models on the market. It is also a convenience to have two tankless water heaters that can be placed where they are needed near bathrooms and kitchen. Unfortunately, the cost is quite a bit higher, but you should make up the cost difference in energy and water savings.  Living in California saving water is probably more important than saving energy. With the draught that just ended in some parts of California, it is something, I think about all the time.

Summary

When I heard about these standards, I shook my head too.  I saw extra cost and regulations. But living with the changes and what has been achieved, I see the advantages and the benefit it will bring to our lives.  If you are still reading this post and live outside of California, don’t shake your head too much at us Californians. These standards could be coming to your state sooner than you think.  While we are on the bleeding edge, that edge is a lot closer than it was a few years ago. See it as a challenge to design and construction a home that my clients will not have to use off-site energy to run their home.  That is pretty cool.

 

1 Comment

  1. […] an earlier post, I talked about Energy Efficiency &  Net Zero Energy 2020 (NZE 2020).  If you live in California and you want to build a new home, your home will have to […]

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