OK - but what about the most common air/thermal leakage point in the CA homes I've seen: the completely open crawlspace (often with suspended return ducts)? Or the ceiling perforations (access hatch, recessed lights, attic supply duct work), or the (very common) whole-house fan?
Proper/complete retrofits are rarely easily accomplished, and in a mild climate supplied by PG&E, rarely cost-justifiable.
David you are right of course- that is why I made no claims as to the accuracy, I called it a half assed plan. I don’t know Cali- at all. I have not set foot in the state in 28 years. From what I remembered it was fairly warm out in the winter, and most stuff was slab on grade. I was assuming you could ignore the slab, clearly that is not the case if you have vented crawlspaces. I wouldn’t worry about ducts cause I would rip them out.
I am not talking about a “proper” refit There is likely no payback in that. They are likely renovating anyway, so go after the lowest hanging fruit (You are going to change windows and siding anyway- so why not airseal and add outsulation and better windows while you are at it. Now your costs for energy efficiency are only the delta between siding +crappy new windows vs siding + outsulation + better new windows.)
I also indicated I would blower door test it- if the attic access or elsewhere leaked I would fix it- within reason.
Ditto the minisplit approach. If the shell is now ok and the heating system needs updating, It is faster to rip it out and change to a minisplit or 2. IN that mild a climate it should work fine in a 1000 sf house.
I have a hard enough time justifying ROI on improvements in a 6000+ HDD climate where lots of people have oil heat at 3.50-4$ gallon. When people get up over 5000$ a year for heat, then they start to feel enough pain to get interested.
Yes - you and I are in agreement. My response was more for Kaushal; doing a renovation for energy savings is not easy nor often a good payback. My brother and sister-in-law live outside Oakland in a '50s ranch that has had little thermal improvements (just replacement windows IIRC) but their combined gas/electric bill is so low compared to mine (South-East PA) that the only recommendations I could make with a good conscience were for comfort - and they have a whole-house fan in the ceiling and all the duct work/crawlspace/attic hatch I described.
The Passive House standard of.6 ACH @ 50 will be pretty hard to accomplish without stripping down to studs and starting completely over. Even then no easy task. I am not sure that affordable and Passivehus are compatible. The system of Passivehus is great but it is costly. If you can commit the three to four hundred thousand no doubt you can get it done.
Not knowing if there is anything wrong with the house and assuming the bones are good
The question I would ask if I were you is whether or not Georges recommendation of good air sealing and duct sealing and insulation. I would add if you have a raised foundation a vapor barrier with an astm 1745 material mechanically fastened to stem wall and sealed. Efficient lighting, mechanical ventilation and a good energy saving refrigerator. insulate all hot water lines put a blanket on DWH it and for less than 15k I would think maybe even as low as 10k you have allot more bang for your buck.
Another 8k will get you solar water heater. Another 15k should get more than enough juice for PV to get you close to net zero. Allot less capitol and big results
I've been involved with a number of Passive House retrofits in California, including the first one in the state (the O'Neill residence in Sonoma) and Kurt & Chie's home in Santa Cruz, and I would say, #1, "Don't fix what ain't broke!" That is not a cost-effective approach in any circumstance. Beyond that, you need to look for "value-add" opportunities (wiring, plumbing, etc.), and be sure you don't miss any. Yes, Passive House is a holistic, ambitious and thorough approach, but in milder climates especially, with careful planning, the delta between what one might do anyway and getting to Passive House can be a smaller up-front expense than you might expect. When coupled with rebates, long-term utility savings, and less tangible value items like comfort, indoor air quality and contributing to positive social change, it can be a great answer! I don't know anyone with a Passive House who feels it wasn't worth it.
Thanks Graham for that. It was also my belief that the cost difference between remodeling and doing a passive house retrofit wouldn't be that great. It is good to hear that from someone with experience.
My wife and I are doing something similar to our house in Walnut Creek (1951, 1,200 sf) through the Energy Upgrade California program. I've been writing about it here in Home Energy Pros. Feel free to check it out and let me know if you'd like to discuss off line.
Here are links to two blog posts:
Thanks Jim! I'll be sure to check that out.
Wow...thank you so much for your response Alice! I really appreciate it. It is simply amazing all that you were able to do in your renovation. It's also quite interesting to leave the current exterior wall and put one on top of the other one. We will certainly look into that. I really like it that it saves the environment from all the demo work and trash.
I am curious if you did some or most of this work yourself to keep the costs down.
Thanks again Alice! Your project gives me hope. Thank you.
I tried sending you an e-mail but the message bounced. Can you kindly verify your e-mail address? Thank you!
I just spent more than an hour on a detailed response and lost when I decided to check the most recent comment. Here is the short version!
I suggest you check out these two attachments. They are also posted under the Resources page www.thousandhomechallenge.org. Also consider participating in the Thousand Home Challenge - and join the group by that name on HEP (if you haven't already)
Great idea to embark on a deep energy retrofit project with the goal of maximizing sweat equity. Doing so collaboratively with others who share your goals could achieve a high performance homes within a reasonable and affordable budget. Balancing sweat equity with an appropriate investment in design and construction experience is essential.
Hopefully, Home Energy Pros can link you identify others in the Bay area who share your goals. Through the Thousand Home Challenge I know of some Bay area homeowners and energy/design professionals & contractors who may be interested in participating in some capacity.
It would be great to get funding to pay for a trainer/consultant/contractor to provide technical and onsite support for a group of a dozen or so homeowners and volunteers. Or, maybe a group of folks who share a common goals would choose to hire one person to coordinate their efforts - and doing so would save money and generate projects that benefit from each others ideas, skills, and energy. This approach has been used for self-help housing in rural areas for years. Why not embark on an Bay area flavor of DIY deep energy retrofits? Having a licensed and experience point person could be very important to getting through permitting requirements. Your local Habitat for Humanity affiliates may be able to provide insight on overcoming local barriers.
I look forward to following your process and project.