At RKM Homes we design each custom house to respond to the realities of Colorado sun and site conditions. Denver sits at roughly 39.7° N latitude, which means the noontime sun climbs to about 74° above the horizon at the summer solstice and falls to roughly 27° at the winter solstice. Those seasonal extremes — long, high-angle summer days and low-angle, bright winter days (often amplified by snow reflection) — strongly influence passive heating and cooling potential, daylighting, glare, and the placement of outdoor living spaces. Mountain silhouettes, neighboring buildings, mature trees and prevailing winds on a specific lot can cast critical shadows or create microclimates that make a one-size-fits-all orientation ineffective.
Practical design responses start with room placement and window strategy: primary living areas and large glazed surfaces generally perform best with a southern or southeast exposure to capture winter sun and provide steady daylight, while east-facing bedrooms take advantage of morning light and west-facing glazing is minimized or heavily shaded to reduce late-afternoon overheating. Roof surfaces and ridgelines should be arranged to maximize south-facing area for photovoltaic arrays when feasible, and overhang depths are sized to block high summer sun while admitting low winter sun based on the sun-angle numbers above. We also specify glazing types, thermal mass placement, operable shading, and landscaping (deciduous trees for summer shade, evergreen windbreaks for winter) to fine-tune comfort and energy use.
Our process translates sun-path analysis into concrete decisions early in the design: site surveys, sun-path diagrams and 3‑D shadow studies inform orientation options, window locations, overhang dimensions, and photovoltaic siting so choices are optimized for comfort, energy performance and the client’s priorities like views and privacy. Because every lot brings different constraints — slope, setbacks, existing vegetation, neighbors, and HOA or code limits — orientation becomes a calibrated compromise. We work with clients to weigh those trade-offs and deliver a custom orientation that leverages Denver’s solar resources while addressing shading, glare and seasonal comfort.
Site solar access and shading analysis
How do I evaluate solar access and existing shading on my lot so the house sits where it will get the sun I want? As builders we start every custom project with an on-site solar access and shading check: walk the lot at key times (solar noon, mid-morning and mid-afternoon) on representative dates, record locations of mature trees, adjacent buildings, fences and ridgelines, and note orientations with a compass. Use a simple clinometer or a smartphone sun-path app to read solar altitude at noon on the winter solstice and summer solstice; photograph the same views at those times so you can compare shadow extent. Also pull the site survey or Google Earth imagery to scale so your field notes can be plotted onto the lot plan.
What measurements and simple calculations will tell me how far shadows will reach and when? Measure the height of any tall objects you can’t move (trees, poles, neighboring roofs) and the horizontal distance to proposed building footprints or outdoor living areas, then use the shadow-length rule: shadow length = object height / tan(solar altitude). For Denver (≈39.7° N) expect a solar noon altitude of roughly 27° on the winter solstice, ~50° at equinox, and ~74° on the summer solstice — so a 30-foot tree casts about 59 feet of shadow at winter noon, ~25 feet at equinox, and under 9 feet at summer noon. Plot those worst-case winter shadows on your lot plan to identify “no-go” zones for primary living spaces and to decide which trees will need trimming or protection.
What decisions should that analysis drive when we set the house footprint and landscape? Use the mapped shadows and access lines to place the house, patios and primary windows where midday winter sun lands and to avoid long winter shade over south-facing areas; identify where you can retain shade for summer comfort without compromising winter solar gain; and reserve unobstructed corridors if you plan future solar equipment or large south-facing glazing. For tricky parcels or sub-30-foot setbacks, we recommend a professional shadow study (or a drone survey) so the orientation and site plan filed for permitting match actual seasonal shading — that one-step analysis will save costly rework and help you protect the trees and views you want to keep.
How do seasonal sun paths and solar angles affect the orientation of my custom home on a lot?
I look at seasonal sun paths first because the sun’s altitude and azimuth tell you where and how strongly light and heat will hit the house through the year. At our Denver latitude the sun at solar noon climbs to roughly 74° above the horizon on the summer solstice and drops to about 27° at the winter solstice. That large swing means the high summer sun can be shaded with modest roof overhangs while the low winter sun penetrates deeper into a south-facing space — a predictable pattern you can use when deciding which side of the lot should host main living areas versus service spaces.
On site I do a quick, practical check: find true south by observing the shortest shadow at local solar noon (or use a smartphone set to true north), then stand where the house will sit and note how late-afternoon and early-morning light move across the lot through summer and winter. If the long axis of the house can be placed within 10–20° of true south, you gain the most consistent midday winter light without exposing long east- or west-facing walls to low-angle glare and heat that are much harder to control. If topography or views force a different orientation, use those solar noon angles to decide which rooms to push toward southern exposure and which to tuck to the north.
You can turn the angles into simple sizing checks while still in schematic design. For example, use the summer solar noon altitude (~74° here) to estimate how deep an overhang needs to be to shade a south window: overhang depth ≈ window head height ÷ tan(summer altitude). A 6-foot head height would only need roughly 1.7 feet of horizontal overhang to block the high summer sun at noon, while the same overhang will not block the low winter sun (tan ≈ 0.51 at 27°), allowing daylight and passive gain. These numbers give you a quick way to test orientation trade-offs on the lot before you finalize the plan or spend on detailed modeling.
How should I orient my custom home and arrange the floor plan to make the most of the sun on my lot?
As a Denver custom home builder I start every layout with the rule of putting the long axis of the house roughly east–west and directing the primary living spaces and largest windows to true south. Practical targets: try to keep the long façade within 10–15° of east–west and concentrate primary glazing within about 20° of true south. That orientation captures low winter sun for passive gain while making it easier to shade high summer sun. Put active day spaces (kitchen, living, dining) and outdoor living to the south/southwest, place bedrooms to the east for morning light, and use utility spaces, garages and closets on the north side as thermal buffers.
When we lay out the plan, we think in room depths and solar access rather than just compass bearings. A good rule of thumb for daylighting: design main living rooms no deeper than about 1.5–2.5 times the window head height (for example, with 8–10 ft high windows that means roughly 12–25 ft of usable daylight depth) or provide clerestories/skylights for deeper plans. Keep second-floor footprints set back or stepped so they don’t cast long shadows over the primary south glazing, and align roof overhangs and window head heights from the start so predictable summer shading works once the orientation is set. If a lot forces you off true south for views or street alignment, staying within 15–20° of south still preserves most of the passive-solar benefit.
On the jobsite and in the design phase I use simple, homeowner-friendly checks: stake the proposed footprint, stand in the rooms at the times you’ll use them (mornings in bedrooms, afternoons in living rooms), and note how sun and privacy play together. Factor in prevailing breezes for cross‑ventilation on side windows, local trees or neighboring structures that could block southern exposure, and HOA/setback limits that may constrain rotation. Balancing solar orientation with views, privacy and circulation is the skill of good custom design — small rotations are often acceptable, but arrange your program so the rooms you live in most face south and use the rest of the plan as a buffer.
Where should I place windows, what glazing should I use, and which daylighting or shading devices work best to manage the sun on my lot?
As a custom home builder in Denver I start window placement with the sun path: put the largest, most glazed spaces (living, kitchen, family rooms) on the south side to gain low winter sun and daylight, keep north façades smaller and use moderate glazing on the east for morning light. Because Denver’s solar noon altitude is roughly 74° in summer and 27° in winter, a horizontal overhang sized to block the high summer sun but admit low winter sun works well. A simple rule you can use on-site is D = H / tan(θsummer) (D = overhang depth, H = window height). For our summer angle that’s about 0.28 × window height — a 5‑ft tall south window needs ~1.4 ft of overhang to shade at noon in July while still allowing winter sun down to the sill.
Choose glazing based on orientation and desired heat gain. For our climate I typically specify low‑E, argon‑filled double or triple panes with a U‑factor in the 0.20–0.30 range for good year‑round performance. For south windows where you want passive winter heat, use a higher SHGC (around 0.40–0.60); for east and especially west exposures use a lower SHGC (≤0.25) or add exterior shading because low‑angle morning and evening sun can overheat rooms. Exterior shading (fixed overhangs on the south, vertical fins on the east/west, or operable exterior screens) cuts heat far more effectively than interior blinds, so specify exterior devices when possible.
For daylighting and occupant comfort, incorporate clerestories, light shelves and well‑placed skylights to bring diffuse light deep into living spaces while minimizing direct glare. On east/west façades consider vertical fins, motorized louvers or fixed perforated screens that block low‑angle sun without killing views; ceramic frit or low‑gain glazing can reduce glare on large panes without darkening the room. Ask your builder or architect for a sun‑study and a simple full‑scale mockup (tape the intended window openings and temporary overhangs on the façade) so you can see morning and evening sun penetration before finalizing glass types and shading details.
What roof orientation, pitch and placement will give my custom home the best solar PV performance and passive heating/cooling?
From a builder’s perspective, the single most important decision is to put an uninterrupted south-facing roof plane on the part of the house where you plan to mount solar panels. That usually means running the ridge roughly east‑west so you get a large south slope. Aim to have the main PV array within ±15° of true south for near‑optimal yearly production; if site constraints force a deviation, a slight west bias can be useful for afternoon peak loads. Before framing, walk the lot at solar noon and map shading from trees, chimneys and neighboring roofs — even small, repeated shadows can cut panel output drastically, so orient and locate the roof plane to minimize midday shading.
Choose a roof pitch and PV mounting strategy with both energy and weather in mind. For Denver (around 40° N latitude) a panel tilt close to latitude (about 35°–45°) gives the best year‑round yield; however typical residential roof pitches (4:12 ≈ 18°, 6:12 ≈ 27°, 8:12 ≈ 34°) often don’t match that exactly. If your roof pitch is shallower than ideal, use tilt‑mount racks to increase panel angle; if it’s steeper, you’re already close to ideal and will shed snow better. Plan the roof structure to support the added dead load and wind uplift of panels and racks, and specify mounting details (standing‑seam clamps or flashed through‑mounts depending on material) during framing so flashing, penetrations and conduit runs to the inverter/garage are clean and accessible.
Think about roof overhangs and placement for passive solar control at the same time. Design eaves to shade high summer sun yet admit low winter sun — use the simple geometry D = H / tan(a) where D is overhang depth, H is window height and a is the solar altitude. In Denver the noontime summer altitude is about 74°, so tan(74°) ≈ 3.5 and you’ll need roughly 0.3 × window height to shade at midday summer (an 8‑ft window needs ≈28″ of overhang). Make sure PV panels are positioned so they aren’t shaded by those overhangs or roof features at crucial times, and leave service clearances and access routes for snow clearing and maintenance. Aligning these choices early — roof plane, pitch, overhangs and array placement — avoids costly rework and produces the best combined PV and passive heating/cooling performance.