diff --git a/linopy/expressions.py b/linopy/expressions.py
index 2ab0b8d3..bf7c9dee 100644
--- a/linopy/expressions.py
+++ b/linopy/expressions.py
@@ -963,7 +963,8 @@ def _map_solution(self) -> DataArray:
         Replace variable labels by solution values.
         """
         m = self.model
-        sol = pd.Series(m.matrices.sol, m.matrices.vlabels)
+        M = m.matrices
+        sol = pd.Series(M.sol, M.vlabels)
         sol[-1] = np.nan
         idx = np.ravel(self.vars)
         values = np.asarray(sol[idx]).reshape(self.vars.shape)
diff --git a/linopy/matrices.py b/linopy/matrices.py
index e694a720..21b50d2d 100644
--- a/linopy/matrices.py
+++ b/linopy/matrices.py
@@ -7,6 +7,7 @@
 
 from __future__ import annotations
 
+from functools import cached_property
 from typing import TYPE_CHECKING, cast
 
 import numpy as np
@@ -96,7 +97,7 @@ def _build_cons(self) -> None:
             np.concatenate(sense_list) if sense_list else np.array([], dtype=object)
         )
 
-    @property
+    @cached_property
     def c(self) -> ndarray:
         """Objective coefficients aligned with vlabels."""
         m = self._parent
@@ -121,7 +122,7 @@ def c(self) -> ndarray:
         np.add.at(result, label_to_pos[var_labels[mask]], coeffs[mask])
         return result
 
-    @property
+    @cached_property
     def Q(self) -> scipy.sparse.csc_matrix | None:
         """Quadratic objective matrix, shape (n_active_vars, n_active_vars)."""
         m = self._parent
@@ -130,7 +131,7 @@ def Q(self) -> scipy.sparse.csc_matrix | None:
             return None
         return expr.to_matrix()[self.vlabels][:, self.vlabels]
 
-    @property
+    @cached_property
     def sol(self) -> ndarray:
         """Solution values aligned with vlabels."""
         if not self._parent.status == "ok":
@@ -146,7 +147,7 @@ def sol(self) -> ndarray:
             result[positions] = var.solution.values.ravel()[mask]
         return result
 
-    @property
+    @cached_property
     def dual(self) -> ndarray:
         """Dual values aligned with clabels."""
         if not self._parent.status == "ok":