Item 3
Plain English
The state of California has very specific and rather stringent
energy conservation standards, usually called "Title 24." If you
honestly can state that your existing building contains a functioning
heater of any size, the work you are doing is considered to be
an alteration of heated space rather than creation of new conditional
space; you therefore do not need to touch the envelope of the
building– i.e. windows, walls, roof, doors –for purposes of energy
conservation. On the other hand, if your design complies entirely
with the "prescriptive heating requirements" as specified in section
329B.6, the space in question is considered "unconditioned," which
means it does not require Title 24 energy calculations.
HINT: There is, however, a conflict. The prescriptive heating
requirements–a default set of requirements for live/work intended
to simplify requirements and avoid the need for Title 24 calculations--
dictate a certain level of heat delivery as well as insulation
of walls and ceiling of the heated space(s). Therefore, a conflict
arises between the above permission to leave the envelope alone
and the prescriptive insulation requirements.
Resolving this conflict can be difficult in large existing buildings,
particularly those combining wood frame floors and interiors with
masonry or concrete exterior walls, a very common early 20th century
building type, and one favored for conversion by today’s live/work
developers. Pending resolution of this inconsistency, one choice
is to commission a computer-generated set of Title 24 calculations,
which will usually contain recommendations for added insulation,
possible window changes, and other alterations. Such construction
can be expensive, especially if not otherwise necessary. Most
all-concrete or masonry buildings have sufficient "thermal mass"
which means that when a Title 24 calculation (usually costing
$150-400) is run on them they do not require significant building
envelope modifications.
A good direction for addressing heat and insulation issues, suggested
by Building Department staff, is that in a building which has any
pre-existing heat, conform to the prescriptive heating requirements,
add thermal insulation to the roof and any wood frame exterior
walls to comply with all prescriptive requirements, but do not
upgrade exterior windows (other than making them relatively water-tight)
and do not alter (or insulate) masonry or concrete walls.
In any event, whatever energy calculations or prescriptive standards
are being employed should be noted under this section, itemized
by unit if there is variation. Please see the example in the appendix.