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The installation of HVAC (Heating, Ventilation and Air Conditioning) is regulated, in California,
in large part by Title 24.
The Energy Commission adopted the 2005 changes to the Building Energy Efficiency Standards, for a number
of compelling reasons:
- To respond to California's energy crisis to reduce energy bills,
- Increase energy delivery system reliability, and
- Contribute to an improved economic condition for the state;
- To emphasize energy efficiency measures that save energy at peak periods and seasons,
- Improve the quality of installation of energy efficiency measures,
- Collaborate with California utilities
And so, in October 2005, the new regulations of Title 24 went into effect determining the types of HVAC systems allowed
to be installed and the way the HVAC systems should be insulated and sealed. California issued a
Letter to the home owners in regards to this law change.
You will find below an attempt to show how Title 24 influences Californian home owners
in their choice of HVAC system.
The exact law and the details on this topic can all be read about it by directly visiting
the official website of California Energy Commission .
The rules vary according to the geographical areas of California.
You may check in which zone your home is located by going to
California Climate Zones.
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A few concepts about Air conditioning to better understand the law changes:
Tons and SEER:
Air Conditioning systems are described foremost by two values:
The tonnage and the SEER.
The number of tons indicates what space can be cooled by the system while the number of SEER
indicates the efficiency of the system, i.e. how much energy it requires to cool down the designated area.
By analogy, the SEER for AC is the equivalent of how many miles per gallon a car uses while the tonnage
represents how many cylinders the car’s engine has.
Practically the tonnage is determined by the size of the house or office to be cooled.
The choice of the number of SEER used to be up to the home owner. Generally home owner who
relatively rarely used their Air Conditioning system used to choose to spend their money
on their electric bills while home owner who used their air conditioning more than 4 hours
a day for more than 4 months a year would invest in a more efficient system. This approach
is still valid. However since the recent law change, California imposes some restriction on
the SEER of the units newly installed or replaced.
Thermostatic Expansion Valve:
The amount of refrigerant circulated through the air conditioning system can be finely adjusted
by using a special device called thermostatic expansion valve or TXV. The use of this type of
expansion valves results in decreased energy consumption as the compressor does not always
have to pressure the full amount of refrigerant.
Ducts:
The ducts transfer and distribute the air blown by the blower fan motor through either the heating
or the cooling element to the house. The amount of cold (or heat) collected by the air just before
entering the ducts should optimally be provided to the area to be cooled down (or warmed up)
without any loss during its transport. In order to reduce the cool (or heat loss) during the
traveling through the ducts, ducts are insulated.
New standards of insulations have recently been implemented and the minimum insulation required is
a rating of R6.
Beside losing cool (or heat) the air may also be lost on its way when the ducts are not perfectly sealed.
Connections between ducts generally hold through duct tape whose glue dries out as time goes by.
Older ducts tend to become porous. Altogether studies indicate that ducts that are 10 years or older
tend to leak an average of 20 to 30%.
Loss of cold (or heat) before reaching the habitable rooms and loss of air altogether represent major
energy losses. Besides who wishes to cool the attic down?
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In view of the fact that residential appliances, including heating and cooling equipment
and water heaters, consume 90% of all energy used in the U.S. residential sector and that
though accounting for only 5 percent of the world's population, Americans consume 26 percent
of the world's energy (Ref.)
there is an obvious need for controlling the energy consumption in this state.
Although there is considerable technical potential to improve the energy efficiency of California
-- and for that matter, the rest of the United States -- California, the most populous in the nation,
has one of the lowest rates of energy consumption compared with other states.
Of the 50 states, California has the fourth lowest energy consumption per capita.
And, among the 19 most populous states -- those with more than five million people --
California ranks second, trailing only New York. (Ref.)
This success in limiting the growth rate of California's consumption of electricity per capita and per GDP
(which are considerably below that of the United States as a whole) comes at a cost to home owners.
Many of you may remember that in the summer 2006 when it was so hot, cities, like New York,
asked their citizen to limit their energy consumption in all domains except in the field of
air conditioning.
California implemented nearly a year before that, a different type of policy: namely limit the energy wasted
when using air conditioning by requesting all home owners to select a more efficient HVAC system
when they replace an existing system or install a new one.
The aim of California is to optimize the residential and commercial Air Conditioning systems
in order to reduce their energy consumption.
Air conditioning systems consume more energy than they need to because:
- the systems have a low efficiency,
- The system always circulates the maximum amount of refrigerant available
- the area to be cooled down is badly insolated or
- the air sent to cool the inhabited space is lost on the way.
So California addresses those issues by requiring that home owners upgrade or improve
their air-conditioning system whenever a major component of their HVAC
system is being replaced.
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SEER:
The aim is to have home owner install higher efficiency units with a minimum of 13 SEER and even 14 SEER
in a close future. The way California achieves this is by having forbidden the manufacture of 10 SEER
or less since the summer 2005 and by forbidding the installation of units below 13 SEER when those
have been manufactured after January 23, 2006. As long as AC systems which have been manufactured
before January 23, 2006 are available on the market, those can be installed independently of their SEER.
In all cases the Air Conditioning systems manufactured after January 23, 2006 must have an efficiency
of at least 13 SEER.
TXV
In most cases, when an air conditioning system is being replaced, the home owners are requested to add
a thermostatic expansion valve (TXV) to the evaporator coil (if it does not have it yet). The addition
of the TXV allows the optimization of the refrigerant circulation, thereby facilitating the work of the
compressor ultimately leading to a reduction in energy consumption. When a new air conditioning system
is installed the cooling coil should also come with a thermostatic expansion valve.
DUCT:
In order to limit the losses due to air leak, the new California Law for title 24 requires in many zones
that the ducts be sealed (and partially replaced if necessary) so that the air leakage may be maintained
to the minimum amount possible. If the air conditioner is being replaced, then the air leakage should
be below 15%. If it is a new installation, the air leakage should be below 6%.
By law the air leakage level needs to be measured by a third neutral party, generally a HVAC contractor
with the license to do HERS INSPECTION . Some of the certified HERS raters are listed by
Calcerts . But there are other sites which can help you
locate other HERS raters.
There are a couple of circumstances that exempt one from having to undergo HERS inspection:
- The property belongs to a geographical zone which does not require HERS inspection
- Install an air conditioner system with a high efficiency: 14 SEER and higher
- Asbestos ducts
- Less than 40 feet of exposed ducts.
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If you are a home owner and wants to either replace your air conditioning system or install
a full new system, you must abide by the California law. Moreover replacement of any major
part of the air conditioning system requires a city permit. Cities must at least respect
the California law but they can also demand more than California does. For example some
cities are already asking for 14 SEER as the minimum efficiency.
In summary, the replacement or installation of a new Air Conditioning system requires that
a home owner checks at least the following points:
- what geographical zone he/she belongs to
- SEER that is allowed in his/her area/city
- Requirement for the installation of a cooling coil with TXV or addition of a TXV to an existing cooling coil
- Requirement for a HERS Inspection.
In doubt, feel free to call us and we will answer your questions or guide you to find the answers matching
your specific case.
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