# Will It Be Bright?

> Free natural light calculator for home buyers. Paste an address, Zillow link, or Redfin link and get a brightness grade based on compass orientation and seasonal sun angles.

## Tool
- [Sunlight Calculator](https://willitbebright.com/): Analyze any US address for natural light exposure by time of day and season
- [About](https://willitbebright.com/about/): Who built this and how the sunlight calculation actually works

## Guides
- [South-Facing House Sunlight](https://willitbebright.com/south-facing-house-sunlight/): Seasonal sunlight patterns, room-by-room impact, energy savings, and when south-facing isn't actually best
- [North-Facing Apartment Sunlight](https://willitbebright.com/north-facing-apartment-sunlight/): Why north-facing gets unfairly dismissed, floor level impact, and how to maximize light
- [East vs West Home Sunlight](https://willitbebright.com/east-vs-west-home-sunlight/): Hour-by-hour comparison, temperature and energy costs, and which fits your lifestyle
- [Best Home Direction for Natural Light](https://willitbebright.com/best-home-direction-natural-light/): All 8 compass directions ranked with decision matrix for different priorities
- [How the Sunlight Score Works](https://willitbebright.com/how-sunlight-score-works/): Methodology — orientation detection, sun position math, seasonal variation, and confidence scoring
- [Zillow Sunlight Checker](https://willitbebright.com/zillow-sunlight-checker/): Check natural light from any Zillow listing URL
- [Redfin Sunlight Checker](https://willitbebright.com/redfin-sunlight-checker/): Check natural light from any Redfin listing URL
- [Which Way Does My House Face?](https://willitbebright.com/which-way-does-my-house-face/): 4 methods to find your home's compass orientation fast
- [Apartment Sunlight Guide](https://willitbebright.com/apartment-sunlight-guide/): Complete guide for renters — floor, unit position, direction, and dark apartment fixes
- [Home Sunlight Tour Checklist](https://willitbebright.com/home-sunlight-tour-checklist/): 12 things to check for natural light before buying a home
- [Natural Light & Home Value](https://willitbebright.com/natural-light-home-value/): Does natural light increase home value? Data on premiums, buyer preferences, and appraisal factors
- [Sunlight Hours by City](https://willitbebright.com/sunlight-hours-by-city/): 30 US cities compared — annual sunshine hours, best orientation, and regional advice
- [Sunlight & Energy Efficiency](https://willitbebright.com/sunlight-energy-efficiency/): How home orientation saves 10-20% on heating — passive solar, window ratios, and DOE data
- [Home Sunlight by Season](https://willitbebright.com/home-sunlight-by-season/): How the same home changes from winter to summer — sun angles, light hours, and seasonal impact
- [Natural Light Home Office](https://willitbebright.com/natural-light-home-office/): Best window direction for WFH — productivity data, desk placement, and video call lighting
- [Sunlight for Indoor Plants](https://willitbebright.com/sunlight-for-indoor-plants/): Does your home get enough light for plants? Window direction guide with lux ranges and species picks
- [Sunlight & Mental Health](https://willitbebright.com/sunlight-mental-health/): How your home's light affects mood — SAD, circadian rhythm, and morning light research
- [Too Much Sunlight](https://willitbebright.com/too-much-sunlight-home/): UV damage, fading, heat management — protecting your home from excess sun exposure
- [Feng Shui & Vastu](https://willitbebright.com/feng-shui-vastu-home-direction/): Where ancient traditions and sunlight science agree on home orientation
- [Natural Light Photography](https://willitbebright.com/natural-light-photography-home/): Best window direction for home studios — portraits, product shots, and golden hour indoors

## Key Facts
- South-facing homes get 6-10 hours of direct sunlight depending on season
- Winter sun at 40°N latitude sits only 27° above the horizon, pushing light deep into south-facing rooms
- Passive solar gain through south-facing windows can reduce heating costs by 10-25%
- North-facing apartments aren't always dark — floor level and window size matter more than direction
- West-facing homes cost 10-20% more to cool than east-facing due to compounding afternoon heat
- Workers with window access report 56% less drowsiness (Cornell study)
- Natural light can add a 2-5% premium to home sale prices
- About 5% of US adults experience Seasonal Affective Disorder; home orientation affects winter light exposure
- North-facing windows provide consistent ~5,500K light ideal for photography
- The tool estimates orientation from building footprints and road geometry, then calculates sun position for every 30-minute interval