Bunker Systems
Power: solar, batteries and a generator behind them.
Every other system runs on power: the air blower, the well pump, the dehumidifier, the refrigerator, the radios. A bunker power system is sized for the shortest days of the year, keeps its batteries warm, and has a generator and stored fuel for the weeks the sun does not cooperate.
Three tiers
Priced,
installed.
Every Builder bunker includes at least the Essential tier, and larger bunkers require a larger tier. Prices are installed in Utah, including equipment, labor and commissioning, and are confirmed in writing after the site visit.
Essential
$27,500installed
Solar and storage for a small household's critical loads.
- Hybrid inverter (EG4 18kPV class)
- 20 kWh LiFePO4 battery bank
- About 5 kW of solar in buried conduit
- Whole-system surge protection
Household
$54,500installed
Twice the storage plus automatic standby generation.
- Hybrid inverter with 30 kWh LiFePO4 storage
- About 10 kW of solar
- Generac 22 kW propane standby generator with transfer switch
- 500-gallon propane tank and surge protection
Estate
$106,000installed
A hardened power plant for long, dark winters.
- Sol-Ark 15K inverter and about 55 kWh of storage (Fortress eVault class)
- About 15 kW of solar on hardened buried conduit
- 20 kW diesel standby generator with 500-gallon tank
- Surge arrestors on AC, DC and solar lines; spare charge controller in Faraday storage
How we size it
The numbers
behind it.
Daily load
Our planning estimate is 12 to 15 kWh a day for four people and 25 to 35 kWh for twelve: the NBC blower, a dehumidifier, lighting, a refrigerator, UV water treatment, communications and cooking.
December, not June
Solar is sized for the shortest days and snow cover, and the battery bank for about two days without sun.
Cold batteries
Lithium batteries must not be charged below 32°F, so the bank lives inside the bunker or a conditioned power room, with low-temperature charge protection.
Medical loads
A home oxygen concentrator can draw 350 watts, about 8.4 kWh a day if it runs continuously. Tell us about medical equipment and we size for it.
Questions
About
power.
Is a generator really needed with solar?
For a household that must hold through winter, yes. Several cloudy days in a row will drain any affordable battery bank, and a standby generator with stored fuel bridges them.
Is the system EMP-proof?
We do not claim that, and be wary of anyone who does without test data. Every tier includes surge protection, and the Estate tier adds arrestors on every line and a spare charge controller stored in a Faraday enclosure.
How is the fuel kept usable?
Propane stores indefinitely. Diesel is tested and treated on the schedule NFPA 110 sets for emergency generators, at least annually.
Prices set 2026-10-28 from published retail equipment prices plus installation. Brand names describe the class of equipment; we may substitute equal or better equipment based on availability. Subscriptions, well drilling and septic systems are quoted separately.
Build it your way.
Pick a bunker, choose each system and see the installed price, then reserve with a deposit.