An Accessory Dwelling Unit, or ADU, is a small house you build, perfect for generating extra income, housing family members, or creating your own private space. However, there is a lot that goes into building an ADU comfort home.
You’ll need to obtain permits, select the right appliances, all without forgetting those sneaky extra costs nobody talks about.
This guide to ADU home comfort covers permits, appliances, and the costs of building an ADU home. It’ll help you to make smart decisions, knowing exactly what to expect and how much to budget for your future ADU home.
Building a comfortable ADU costs $60,000 to $285,000, depending on size, location, and finishes. But where does all this money go? Let’s break down everything you need to know about building your dream home.
Choose the Right Appliances, System, Tech, and Materials
To build a comfortable ADU home, you must have the best appliances, systems, and tech that perfectly fit the space.
Building Materials
Choose materials that work hard for your ADU house. These include luxury vinyl plank flooring that costs $3 to $8 per square foot. Laminate will cost you $2 to $6 per square foot, and polished concrete costs $4 to $12 per square foot.
For your ADU walls, drywall with good insulation is standard. Shiplap or board and batten adds character for $5 to $12 per square foot. Outside, fiber cement siding lasts forever and costs $8 to $13 per square foot.
For a window, a double pane is the minimum and costs $300 to $800 per window. Triple-pane windows work better in cold climates for $500 to $1,200 per window. Look for low-E coatings to save energy.
Go for easy-to-clean materials like quartz countertops, which wipe clean easily and cost $60 to $90 per square foot.
Think about noise control. Sound-dampening insulation will cost you $1 to $3 per square foot, but it makes shared living way better.
Your ADU needs to work for anyone who might live there or visit, from kids to older adults. Create a space where people move around confidently and comfortably. Choose floorings that are resistant but smooth enough for mobility aids. Keep transitions between rooms level and seamless.
Heating and Cooling Systems
Your HVAC system is important when it comes to keeping your ADU comfortable year-round. High-efficiency HVAC systems with higher SEER ratings cost more upfront, from $3,000 to $6,000, but will save you money in the long run through lower energy bills and better performance, especially in small spaces. Window units are cheaper at $300 to $800 but less efficient.
Good airflow offers good comfort for ADU houses. Install exhaust fans in your kitchen and bathroom, and use ceiling fans to move air around. Your ADU should be well ventilated. Small spaces get humid fast, so ensure you keep your furniture away from vents.
Insulation
Insulation is crucial for comfort and savings, especially in small spaces. Proper insulation costs $1,500 to $4,000 upfront but saves $200 to $400 yearly on energy bills.
Small-Size Appliances
When planning to build a comfortable ADU, the types of appliances you choose matter. Remember, this isn’t a regular house. It’s a small space that needs gear specifically designed to work well in tight quarters.
Buy combo units, for example, washer and dryer combos that wash and dry in one machine. This combo costs $1,000-$2,300. Oven and microwave combos work great too, costing $800 to $1,500. Buy a refrigerator with freezer drawers instead of a big side-by-side model.
Size everything down for your ADU. If buying a dishwasher, go for a 24-inch instead of a 30-inch.
Choose Energy Star appliances and look for local utility rebates on efficient appliances.
Smart Tech
When it comes to your tech, buy small thermostats, which save 10-15% on heating and cooling and cost $150 to $300.
Smart lighting makes your space feel bigger and safer. Add a motion sensor for more security and dimming to save energy. The best thing is you get to control everything from your phone. Budget $200 to $500 for your whole ADU smart lighting. Switch to LED bulbs, which cost $100 to $200, and programmable outlets, which cost $20 to $40, for energy savings.
Your ADU security system matters, especially if you’re renting out the space. Buy trusted home security systems, such as Simplisafe or Ring, which may cost about $300 to $800 depending on the features you choose. Take advantage of insurance companies that give discounts for having security systems.
Know Your Source of Power
Your ADU requires its own electrical panel, which costs between $1,500 and $4,000.
If you’re considering solar panels, a small rooftop system costs $8,000 to $15,000, while a portable generator costs $1,500 to $4,000. Luckily, the federal government tax credit covers 30% of costs through 2032.
Get Your ADU Permits Right
ADU permits are like an official permission slip from your city to allow you to build an ADU home. It ensures you’ll build a safe home, up to code, and one that won’t cause problems for neighbors.
Every city has its own rules when it comes to building an ADU home. Your location makes a huge difference in the kind of ADU home you can build and what it’ll cost.
ADU building permit costs range from $8 to $12 per square foot, and total city fees cost you between $3,000 and $11,000. Rural areas have more flexibility to build ADU houses than dense urban areas.
If your city allows attached ADUs (ones that are connected to your main house), your permit cost can range from $500 to $1,500.
California leads as the best city offering ADU-friendly laws, while many states still have strict rules on building an ADU house. Some cities offer reduced permit fees to encourage ADU construction.
What’s the process of getting an ADU home permit?
ADU Home Permit Process
Here are the forms you need to process your ADU house permit.
- Building permit applications may cost between $2,000 and $10,000.
- Site plan showing your property layout. The plan review costs an average of $5,000
- Architectural drawings. Architectural services cost between $3,000 and $8,000.
- Utility connection costs between $2,000 and $7,000.
- Sometimes, you may need an environmental impact form. For school impact fees, it can cost up to $5,000 (varies by size).
Most of these permit processes take 3 to 6 months. Yes, please plan for delays.
Ways to Save and Avoid Sneaky Costs
When building a comfortable ADU house, take advantage of every tax credit and rebate available. From federal tax credits, local utility rebates, and ADU construction credits.
Get multiple contractor bids and don’t just pick the cheapest. Buy appliances during big sales like Memorial Day and Black Friday. You can also consider finishing some work yourself if you’re handy.
As you build your ADU home, keep in mind extra costs like site preparation, which costs $5,000 to $15,000. It’ll include clearing, grading, soil testing, and dealing with drainage issues.
Trenching is necessary because you need water and sewer lines, electrical connections, and maybe internet and cable. It’ll cost you $3,000 to $8,000.
Surprise upgrades happen all the time. It could be your electrical panel, which may cost you $2,000 to $5,000 to upgrade. Your water meter can call for a fix costing you $1,000 to $3,000, or your sewer capacity issues, which can hit $3,000 to $10,000.
Bottom Line
Building a comfortable ADU house costs $60,000 to $285,000 in total, depending on size, location, and finishes. The cost will include permits, your choice of appliances, tech, heating and cooling systems, building materials, and more.
Start with permits because they take forever. While you wait, research appliances, tech, and materials. Get multiple contractor bids and put everything in writing. Budget 20% more than you think you’ll need for those sneaky costs. By doing so, your ADU will surely be an incredible investment and a comfortable home for everyone who will live there.
