---
title: "Warm shell — Class A Atlas glossary"
description: "Core and shell plus base HVAC, lighting, and floor."
canonical: https://classa.info/glossary/warm-shell
pageType: glossary
lastUpdated: 2026-04-01T00:00:00.000Z
license: "CC BY 4.0 with attribution to Class A Atlas (https://classa.info)."
---

> Core and shell plus base HVAC, lighting, and floor.

## TL;DR

- Core and shell plus base HVAC, lighting, and floor.
- An intermediate delivery condition: more than core and shell (HVAC trunk lines and base lighting are in), less than turn-key.

# Warm shell

*Construction · US*

## Short definition

[Core and shell](/glossary/core-and-shell) plus base HVAC, lighting, and floor.

## Full definition

An intermediate delivery condition: more than core and shell (HVAC trunk lines and base lighting are in), less than turn-key. Common for spec suites and pre-built inventory.

## Why this matters for Class A leasing

Warm shell is part of the construction vocabulary that institutional [Class A](/glossary/class-a) occupiers, landlords, and advisers use across US markets. Understanding it correctly affects how you read lease documents, model occupancy economics, and benchmark deal terms across cities. Class A Atlas tracks the US definition alongside the global standard so [cross-border](/topics/cross-border-expansion) occupiers can translate quickly.

## Related topics

- [**Fit-out Capex**](/topics/fit-out-capex) — How to budget, sequence, and govern Class A office [fit-out](/topics/fit-out-capex)">fit-out capex.
- [**US TIA Strategy**](/topics/us-tia-strategy) — How to negotiate, draw down, and account for US tenant improvement allowances (TIA).

---

Citation: Source: Class A Atlas (https://classa.info/glossary/warm-shell), updated 2026-04-01T00:00:00.000Z.