Autonomy scoreLocal analysis
Washington Home autonomy potential in Washington (20001)
The strongest asset here is Rainwater. It is not, however, what pays your home the most: that is Low-carbon heating.
Annual potential, standard home
$2,705
Four items added up — each one is a separate decision, in whatever order suits you.
Overall score
56 /100
Growing
Washington: 56/100 achievable autonomy with a recommended setup.
Solid potential — real, achievable gains in energy, water & food autonomy await.
What you could reach in Washington
A typical home in Washington can reach about 56% self-sufficiency with a right-sized solar, storage, rainwater and low-carbon heating setup — most of it backed by federal tax credits. The figure sharpens once you enter your own home.
- ≈167 days a year off the grid — keep the fridge, lights, router and heating pump running straight from your own roof and battery, right through a winter outage.
- Rainwater self-reliance — ≈97,920 L harvested from a 100 m² roof covers the garden and toilet flushing, so hosepipe bans stop mattering.
- A real harvest — ≈263 kg of fresh vegetables over a ≈230-day frost-free season takes a genuine bite out of the weekly shop.
- A warm, low-bill winter — insulation plus a right-sized heat pump turns the local climate into low-carbon comfort and shields you from gas-price spikes.
From the most to the least profitable, here
What you could gain
-
Low-carbon heating61/100
~$1,233/yr
less heating after insulation + heat pump (−7,470 kWh/yr on 90 m², electric heating)
The detail
Realistic outlook
2,400 heating-degree-days: a high-efficiency heat pump is the lowest-carbon way to keep Washington warm.
Watch-outs
A heat pump only pays off in a well-insulated envelope — insulate first, then size the unit.
Incentives & tips
Energy Efficient Home Improvement Credit (§25C): up to $2,000/yr for heat pumps plus credits for insulation; HEEHRA state rebates may stack.
Heating-degree-days (base 18°C) : ≈ 2,400 HDD — Source: PVGIS, hourly ERA5 temperatures 2005–2015 (base 18°C).
-
Food growing60/100
~$736/yr
off the weekly shop — up to ≈263 kg/yr of fresh vegetables from 100 m²
The detail
Realistic outlook
With about 230 frost-free days, a household garden in Washington supports two planting rotations a year.
Watch-outs
A productive garden needs space, decent soil and a few hours a week — start small and scale up.
Incentives & tips
USDA People's Garden and many municipal community-garden and composting programs support home food production.
Frost-free growing season : ≈ 230 days — Source: PVGIS, hourly ERA5 temperatures 2005–2015 (frost dates).
-
Solar energy37/100
~$536/yr
less electricity with 3 kWp on your roof (≈4,125 kWh/yr)
The detail
Realistic outlook
At 1,375 kWh/kWp per year, Washington offers moderate potential for residential rooftop solar.
Watch-outs
Roof orientation, shading and local interconnection rules affect real output — get a site assessment first.
Incentives & tips
Federal Residential Clean Energy Credit (IRA §25D): 30% tax credit on solar PV and battery storage through 2032.
Annual PV yield : 1,375 kWh/kWp — Source: PVGIS 5.2 (EU Joint Research Centre), optimal tilt and local horizon.
-
Rainwater80/100
~$200/yr
less mains water with a 5,000 L tank (≈97,920 L/yr harvestable from a 100 m² roof)
The detail
Realistic outlook
1,152 mm of rain a year makes rooftop rainwater harvesting highly productive in Washington.
Watch-outs
Harvested rain is non-potable by default — keep it separate from drinking water and add a first-flush diverter.
Incentives & tips
Rainwater incentives vary by state — e.g. Texas sales-tax exemption on harvesting equipment, local rebates in Arizona. Check state and city programs.
Average annual rainfall : 1,152 mm — Source: NASA POWER, MERRA-2 corrected precipitation.
$2,705
Ranked by annual value. The order of the works themselves does not change: insulate before you equip.
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Estimate your solar system in Washington
Estimate your solar system in Washington
Based on a local yield of 1,375 kWh/kWp per year.
Indicative estimate (production = kWp × local yield). Real output depends on roof orientation, shading and your self-consumption rate.
Climate month by month in Washington
In Washington, a 3 kWp array pitched at 36° and facing due south — the optimum PVGIS computes for this location — produces about 4,125 kWh a year. May is the strongest month, at about 399 kWh, and December the weakest, at 249 kWh. November to February still bring 28% of the year's output, so the system stays useful all winter and a battery pays its way year-round.
The heating season runs from October to April: 7 months average below 59 °F (15 °C), and January is the coldest at 35 °F (1.4 °C). In a typical year the coldest hours drop to about 19 °F (-7 °C), the point a heat pump has to be sized for: a standard air-to-water heat pump copes comfortably in an insulated house.
Frost is possible until late March and returns from mid-November, which leaves about 230 frost-free days; tender crops such as tomatoes, beans and squash go outside once late March is past. Expect about 55 days above 86 °F (30 °C): shade netting and mulch matter as much as frost protection, and the water tank is drawn hardest in July.
With a mean wind of 5 mph (2.3 m/s) at 10 m, a small rooftop turbine would produce little in Washington; the roof is better used for solar. The southern horizon is open (at most 4.2°) in PVGIS's elevation model, so low winter sun reaches roofs unless nearby buildings block it.
Compared with Baltimore, 35 miles away, Washington has the same solar yield, 8 fewer frost-free days and a heating need 2% lower. Compared with Philadelphia, 123 miles away, Washington has 1% more solar yield, 12 more frost-free days and a heating need 7% lower.
| Month | Mean temperature | Solar output, 3 kWp |
|---|---|---|
| January | 35 °F (1.4 °C) | 288 kWh |
| February | 35 °F (1.4 °C) | 315 kWh |
| March | 44 °F (6.6 °C) | 369 kWh |
| April | 55 °F (13.0 °C) | 387 kWh |
| May | 65 °F (18.4 °C) | 399 kWh |
| June | 74 °F (23.6 °C) | 387 kWh |
| July | 79 °F (25.9 °C) | 396 kWh |
| August | 77 °F (24.9 °C) | 384 kWh |
| September | 70 °F (21.1 °C) | 339 kWh |
| October | 58 °F (14.5 °C) | 327 kWh |
| November | 47 °F (8.3 °C) | 282 kWh |
| December | 39 °F (4.0 °C) | 249 kWh |
Frequently asked questions — Washington
How much could solar panels generate in Washington?
A well-oriented 3 kWp rooftop array in Washington produces about 4,125 kWh a year, worth roughly $536 in self-consumption. A 6 kWp system reaches about 8,250 kWh/yr where the roof allows. Federal Residential Clean Energy Credit (IRA §25D): 30% tax credit on solar PV and battery storage through 2032.
Is rainwater harvesting worth it in Washington?
Yes. A 60 m² roof in Washington can capture about 58,752 litres a year for the garden, WC and washing machine. Keep harvested rain separate from drinking water and fit a first-flush diverter. Rainwater incentives vary by state — e.g. Texas sales-tax exemption on harvesting equipment, local rebates in Arizona. Check state and city programs.
What grants help with low-carbon heating in Washington?
Energy Efficient Home Improvement Credit (§25C): up to $2,000/yr for heat pumps plus credits for insulation; HEEHRA state rebates may stack. Insulate first — a heat pump only pays off in a well-insulated home (2,400 heating-degree-days here), so prioritise the roof and walls before sizing the unit.
How much food can a garden grow in Washington?
With about 230 frost-free days, a 100 m² garden in Washington yields roughly 263 kg of fresh fruit and vegetables a year — a partial share of a household's needs, not full calorie autonomy. USDA People's Garden and many municipal community-garden and composting programs support home food production.
When is the last frost in Washington?
Frost is possible until late March and returns from mid-November, which leaves about 230 frost-free days; tender crops such as tomatoes, beans and squash go outside once late March is past.
How much does solar produce in winter in Washington?
December is the weakest month: a 3 kWp array makes about 249 kWh, against 399 kWh in May. November to February add up to 28% of the yearly total.
How this score is calculated
Public climate data (PVGIS with NREL's NSRDB radiation) weighted by how vital each dimension is. The score sharpens once you enter your own home. See the full methodology.
Sources
- Solar energy — Source: PVGIS 5.2 (EU Joint Research Centre), optimal tilt and local horizon.
- Rainwater — Source: NASA POWER, MERRA-2 corrected precipitation.
- Food growing — Source: PVGIS, hourly ERA5 temperatures 2005–2015 (frost dates).
- Low-carbon heating — Source: PVGIS, hourly ERA5 temperatures 2005–2015 (base 18°C).
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