Sustainable garage-to-apartment conversion ideas

[jim.bent.winZZ]

I am planning to turn our roughly 20 sq ft two-car garage into a rental apartment because the demand for housing is so high and I want to make the conversion as energy efficient and cost effective as possible.

The current structure is just a concrete slab and wood framing with no heat, plumbing, or insulation, so I need to add walls, a kitchen, and a bathroom, and I will probably replace the main garage door with a wall and windows.

The usual approach would be to use things like rigid foam insulation and a mini-split heat pump, which is fine for permitting, but I am curious about other options, like maybe using dense pack cellulose in the walls or considering high clerestory windows on the south side for passive solar heat, which would help with privacy since that side is right on the property line.

Also, since we are already planning to collect rainwater for the garden, I wonder if there are better ways to handle the water and sewer connections than just hooking up to the city lines, but I need to balance sustainability with cost.

What other smart options for insulation or heating should I look into for this climate, especially since we have that local bargain store for materials?

Thanks for the help!

 

[green ninja]

Have you considered using a dense pack cellulose? I think it is a solid option because it fills gaps well and provides good sound control. The rigid foam is easier but it is best if you pair it with cellulose or mineral wool.

 

[rndomdream]

I wonder if there are better ways to handle the water and sewer connections than just hooking up to the city lines, but I need to balance sustainability with cost.

honestly, stick with the city lines. rainwater is great for gardens, but many municipalities have very strict (and expensive) codes for blackwater and greywater in a rental unit
Off grid systems can hurt your resale value or make it impossible to get a permit
if you want to be sustainable, focus on an ultra efficient heat pump water heater. it’ll dehumidify the garage for free while it heats your water!